diff --git a/jack.cpp b/jack.cpp
index 98fa54b..fa37646 100644
--- a/jack.cpp
+++ b/jack.cpp
@@ -64,6 +64,16 @@ void Client::shutdown_callback(void *arg) {
     client->on_shutdown();
 }
 
+int Client::sync_callback(jack_transport_state_t state, jack_position_t *pos, void *arg) {
+    Client *client = (Client *)arg;
+    /*
+    printf("sync_callback: %i, BBT: %i|%i|%i, BPM: %f, frame: %i\n", 
+        state, pos->bar, pos->beat, pos->tick, (float)pos->beats_per_minute, pos->frame);
+    */
+    assert(pos);
+    return client->on_sync(state, *pos)?1:0;
+}
+
 Client::Client(const char *name) {
     this->name = name;
     handle = NULL;
@@ -94,6 +104,9 @@ bool Client::init() {
 		handle_status(jack_set_sample_rate_callback(
 				handle, &sample_rate_callback, this));
 
+        handle_status(jack_set_sync_callback(
+				handle, &sync_callback, this));
+
 		jack_on_shutdown(handle, &shutdown_callback, this);
         
         for (PortList::iterator i = ports.begin(); i != ports.end(); ++i) {
@@ -125,6 +138,11 @@ void Client::shutdown() {
     
 }
 
+TransportState Client::transport_query(Position *pos) {
+    assert(handle);
+    return jack_transport_query(handle, pos);
+}
+
 void Client::add_port(Port *port) {
     ports.push_back(port);
     if (handle) // port came after init, so post-init it
@@ -137,6 +155,22 @@ void Client::remove_port(Port *port) {
     ports.remove(port);
 }
 
+void Client::transport_locate(NFrames frame) {
+    assert(handle);
+    jack_transport_locate(handle, frame);
+}
+
+void Client::transport_start() {
+    assert(handle);
+    jack_transport_start(handle);
+}
+
+void Client::transport_stop() {
+    assert(handle);
+    jack_transport_stop(handle);
+}
+
+
 //=============================================================================
 
 Port::Port(Client &client, 
diff --git a/jack.hpp b/jack.hpp
index 5f498bf..90a98f5 100644
--- a/jack.hpp
+++ b/jack.hpp
@@ -100,6 +100,9 @@ protected:
 
 //=============================================================================
 
+typedef jack_transport_state_t TransportState;
+typedef jack_position_t Position;
+
 class Client {
     friend class Port;
 
@@ -115,9 +118,15 @@ public:
 
     bool is_created();
 
+    TransportState transport_query(Position *pos);
+    void transport_locate(NFrames frame);
+    void transport_start();
+    void transport_stop();
+
     virtual void on_process(NFrames size) {}
     virtual void on_sample_rate(NFrames nframes) {}
     virtual void on_shutdown() {}
+    virtual bool on_sync(TransportState state, const Position &pos) { return true; }
         
 protected:
     void add_port(Port *port);
@@ -132,6 +141,7 @@ protected:
     static int process_callback(jack_nframes_t size, void *arg);
     static int sample_rate_callback(jack_nframes_t nframes, void *arg);
     static void shutdown_callback(void *arg);
+    static int sync_callback(jack_transport_state_t state, jack_position_t *pos, void *arg);
 };
 
 //=============================================================================
diff --git a/jacker.glade b/jacker.glade
index fdc2555..b34853d 100644
--- a/jacker.glade
+++ b/jacker.glade
@@ -92,8 +92,8 @@
                     <child>
                       <object class="GtkImageMenuItem" id="menuitem_song">
                         <property name="visible">True</property>
-                        <property name="related_action">show_song_action</property>
                         <property name="use_action_appearance">True</property>
+                        <property name="related_action">show_song_action</property>
                         <property name="use_underline">True</property>
                         <property name="use_stock">True</property>
                       </object>
@@ -101,8 +101,8 @@
                     <child>
                       <object class="GtkImageMenuItem" id="menuitem_pattern">
                         <property name="visible">True</property>
-                        <property name="related_action">show_pattern_action</property>
                         <property name="use_action_appearance">True</property>
+                        <property name="related_action">show_pattern_action</property>
                         <property name="use_underline">True</property>
                         <property name="use_stock">True</property>
                       </object>
@@ -146,8 +146,8 @@
             <child>
               <object class="GtkToolButton" id="toolbutton1">
                 <property name="visible">True</property>
-                <property name="related_action">play_action</property>
                 <property name="use_action_appearance">True</property>
+                <property name="related_action">play_action</property>
                 <property name="label" translatable="yes">toolbutton1</property>
                 <property name="use_underline">True</property>
               </object>
@@ -159,8 +159,8 @@
             <child>
               <object class="GtkToolButton" id="toolbutton2">
                 <property name="visible">True</property>
-                <property name="related_action">stop_action</property>
                 <property name="use_action_appearance">True</property>
+                <property name="related_action">stop_action</property>
                 <property name="label" translatable="yes">toolbutton2</property>
                 <property name="use_underline">True</property>
               </object>
@@ -310,6 +310,19 @@
                 <property name="homogeneous">True</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkToggleToolButton" id="toolbutton7">
+                <property name="visible">True</property>
+                <property name="use_action_appearance">True</property>
+                <property name="related_action">sync_action</property>
+                <property name="label" translatable="yes">toolbutton7</property>
+                <property name="use_underline">True</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="homogeneous">True</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">False</property>
@@ -702,8 +715,8 @@
     <child>
       <object class="GtkImageMenuItem" id="menuitem5">
         <property name="visible">True</property>
-        <property name="related_action">add_track_action</property>
         <property name="use_action_appearance">True</property>
+        <property name="related_action">add_track_action</property>
         <property name="use_underline">True</property>
         <property name="use_stock">True</property>
       </object>
@@ -749,4 +762,9 @@
     <property name="stock_id">gtk-quit</property>
   </object>
   <object class="GtkAccelGroup" id="accel_group"/>
+  <object class="GtkToggleAction" id="sync_action">
+    <property name="label">Sync</property>
+    <property name="short_label">Sync</property>
+    <property name="tooltip">Sync to JACK Transport</property>
+  </object>
 </interface>
diff --git a/main.cpp b/main.cpp
index 82e4e68..3003c0b 100644
--- a/main.cpp
+++ b/main.cpp
@@ -17,6 +17,7 @@
 #include "player.hpp"
 
 #include "jsong.hpp"
+#include "ring_buffer.hpp"
 
 namespace Jacker {
 
@@ -26,10 +27,22 @@ const char AccelPathPatternView[] = "<Jacker>/View/Pattern";
 const char AccelPathTrackView[] = "<Jacker>/View/Song";
 const char AccelPathSave[] = "<Jacker>/File/Save";
 const char AccelPathOpen[] = "<Jacker>/File/Open";
-    
+
 class JackPlayer : public Jack::Client,
                    public Player {
 public:
+    enum ThreadMessageType {
+        MsgPlay = 0,
+        MsgStop = 1,
+        MsgSeek = 2,
+    };
+        
+    struct ThreadMessage {
+        ThreadMessageType type;
+        int position;
+    };
+    
+    RingBuffer<ThreadMessage> thread_messages;
    
     Jack::MIDIPort *midi_omni_out;
     typedef std::vector<Jack::MIDIPort *> MIDIPortArray;
@@ -37,7 +50,15 @@ public:
     MIDIPortArray midi_ports;
     bool defunct;
 
+    bool enable_sync;
+    bool waiting_for_sync;
+
     JackPlayer() : Jack::Client("jacker") {
+        
+        thread_messages.resize(100);
+        
+        enable_sync = false;
+        waiting_for_sync = false;
         defunct = false;
         midi_omni_out = new Jack::MIDIPort(
             *this, "omni", Jack::MIDIPort::IsOutput);
@@ -57,6 +78,61 @@ public:
         delete midi_omni_out;
     }
     
+    void play() {
+        if (enable_sync) {
+            transport_start();
+            return;
+        }
+        Player::play();
+    }
+    
+    void seek(int frame) {
+        if (enable_sync) {
+            double samples = 
+                (double)frame * (sample_rate * 60.0) / (double)(model->beats_per_minute * model->frames_per_beat);
+            transport_locate((int)(samples+0.5));
+            return;
+        }
+        Player::seek(frame);
+    }
+    
+    void stop() {
+        if (enable_sync) {
+            transport_stop();
+            return;
+        }
+        Player::stop();
+    }
+    
+    void handle_thread_message(ThreadMessage &msg) {
+        switch(msg.type) {
+            case MsgPlay : {
+                printf("SYNC: play\n");
+                Player::play();
+            } break;
+            case MsgStop : {
+                printf("SYNC: stop\n");
+                Player::stop();
+            } break;
+            case MsgSeek : {
+                printf("SYNC: seek to %i\n", msg.position);
+                Player::seek(msg.position);
+            } break;
+            default: break;
+        }
+    }
+    
+    void mix() {
+        ThreadMessage msg;
+        while (!thread_messages.empty()) {
+            msg = thread_messages.peek();
+            handle_thread_message(msg);
+            thread_messages.pop();
+        }
+
+        Player::mix();
+    }
+    
     virtual void on_sample_rate(Jack::NFrames nframes) {
         set_sample_rate((int)nframes);
         reset();
@@ -68,7 +144,86 @@ public:
         midi_ports[msg.port]->write_event(offset, msg);
     }
     
+    int get_frame_from_position(const Jack::Position &pos) {
+        /*
+        if (pos.valid & JackPositionBBT) {
+            int result = model->beats_per_bar * model->frames_per_beat * (pos.bar-1);
+            result += model->frames_per_beat * (pos.beat-1);
+            result += pos.tick * model->frames_per_beat / pos.ticks_per_beat;
+            return result;
+        }
+        */
+        return (int)(((double)model->beats_per_minute * pos.frame / (sample_rate * 60.0))+0.5) * 
+            model->frames_per_beat;
+        //return -1;
+    }
+    
+    virtual bool on_sync(Jack::TransportState state, const Jack::Position &pos) {
+        if (!enable_sync) {
+            waiting_for_sync = false;
+            return true;
+        }
+        
+        bool r_playing = false;
+        
+        switch(state) {
+            case JackTransportStarting:
+            {
+                if (waiting_for_sync) {
+                    if (thread_messages.empty()) {
+                        printf("finished waiting for sync\n");
+                        waiting_for_sync = false;
+                        return true;
+                    } else {
+                        //printf("waiting for sync\n");
+                        return false;
+                    }
+                }
+                waiting_for_sync = true;
+                r_playing = true;
+            } break;
+            case JackTransportStopped:
+            {
+                waiting_for_sync = false;
+                r_playing = false;
+            } break;
+            default: break;
+        }
+        
+        int r_position = get_frame_from_position(pos);
+        if (r_position != get_position()) {
+            ThreadMessage msg;
+            msg.type = MsgSeek;
+            msg.position = r_position;
+            thread_messages.push(msg);
+        }
+        
+        if (r_playing != is_playing()) {
+            ThreadMessage msg;
+            msg.type = (r_playing?MsgPlay:MsgStop);
+            thread_messages.push(msg);            
+        }
+        return false;
+    }
+    
     virtual void on_process(Jack::NFrames size) {
+        if (enable_sync) {
+            Jack::Position tpos;
+            memset(&tpos, 0, sizeof(tpos));
+            Jack::TransportState tstate = transport_query(&tpos);
+            switch(tstate) {
+                case JackTransportStopped: {
+                    if (is_playing() && thread_messages.empty()) {
+                        ThreadMessage msg;
+                        msg.type = MsgStop;
+                        thread_messages.push(msg);
+                    }
+                } break;
+                default:
+                    break;
+            }
+        }
+
         midi_omni_out->clear_buffer();
         for (MIDIPortArray::iterator iter = midi_ports.begin();
             iter != midi_ports.end(); ++iter) {
@@ -94,6 +249,7 @@ public:
     Glib::RefPtr<Gtk::Adjustment> fpb_range;
 
     Glib::RefPtr<Gtk::AccelGroup> accel_group;
+    Glib::RefPtr<Gtk::ToggleAction> sync_action;
 
     Gtk::Window* window;
     PatternView *pattern_view;
@@ -323,6 +479,23 @@ public:
         assert(adjustment);
         return adjustment;
     }
+
+    template<typename T>
+    Glib::RefPtr<Gtk::ToggleAction> connect_toggle_action(const std::string &name, 
+                        const T &signal,
+                        const Glib::ustring& accel_path="") {
+        Glib::RefPtr<Gtk::ToggleAction> action =
+            Glib::RefPtr<Gtk::ToggleAction>::cast_static(
+                builder->get_object(name));
+        assert(action);
+        if (!accel_path.empty()) {
+            action->set_accel_path(accel_path);
+            action->set_accel_group(accel_group);       
+            action->connect_accelerator();
+        }
+        action->signal_toggled().connect(signal);
+        return action;
+    }
     
     template<typename T>
     void connect_action(const std::string &name, 
@@ -348,6 +521,10 @@ public:
         show_song_view();
     }
     
+    void on_sync_action() {
+        player->enable_sync = sync_action->get_active();
+    }
+    
     void init_menu() {
         connect_action("new_action", sigc::mem_fun(*this, &App::on_new_action));
         connect_action("open_action", sigc::mem_fun(*this, &App::on_open_action),
@@ -365,6 +542,7 @@ public:
             sigc::mem_fun(*this, &App::on_show_song_action),
             AccelPathTrackView);
     
+        sync_action = connect_toggle_action("sync_action", sigc::mem_fun(*this, &App::on_sync_action));
     }
 
     void on_bpm_changed() {
diff --git a/player.hpp b/player.hpp
index 90c376e..b9f0995 100644
--- a/player.hpp
+++ b/player.hpp
@@ -50,7 +50,7 @@ public:
 protected:
     class Model *model;
 };
-    
+
 class Player {
 public:
     enum {
@@ -96,7 +96,7 @@ public:
     bool is_playing() const;
     
     void play_event(int track, const class PatternEvent &event);
-    
+        
 protected:
     void premix();
     void mix_events(MessageQueue &queue, int samples);
@@ -117,7 +117,6 @@ protected:
     
     volatile int read_position; // last read position, in frames
     volatile bool playing;
-
 };
 
 //=============================================================================