diff --git a/lib/includes/spdylay/spdylay.h b/lib/includes/spdylay/spdylay.h
index 5dfcacc..3f8358e 100644
--- a/lib/includes/spdylay/spdylay.h
+++ b/lib/includes/spdylay/spdylay.h
@@ -206,6 +206,21 @@ typedef void (*spdylay_on_data_recv_callback)
 (spdylay_session *session, uint8_t flags, int32_t stream_id, int32_t length,
  void *user_data);
 
+/*
+ * Callback function invoked after frame |frame| of type |type| is
+ * sent.
+ */
+typedef void (*spdylay_on_ctrl_send_callback)
+(spdylay_session *session, spdylay_frame_type type, spdylay_frame *frame,
+ void *user_data);
+
+/*
+ * Callback function invoked after DATA frame is sent.
+ */
+typedef void (*spdylay_on_data_send_callback)
+(spdylay_session *session, uint8_t flags, int32_t stream_id, int32_t length,
+ void *user_data);
+
 typedef struct {
   spdylay_send_callback send_callback;
   spdylay_recv_callback recv_callback;
@@ -214,6 +229,8 @@ typedef struct {
   spdylay_on_ping_recv_callback on_ping_recv_callback;
   spdylay_on_data_chunk_recv_callback on_data_chunk_recv_callback;
   spdylay_on_data_recv_callback on_data_recv_callback;
+  spdylay_on_ctrl_send_callback on_ctrl_send_callback;
+  spdylay_on_data_send_callback on_data_send_callback;
 } spdylay_session_callbacks;
 
 int spdylay_session_client_new(spdylay_session **session_ptr,
diff --git a/lib/spdylay_session.c b/lib/spdylay_session.c
index 2a9e223..44e736b 100644
--- a/lib/spdylay_session.c
+++ b/lib/spdylay_session.c
@@ -399,6 +399,18 @@ static int spdylay_session_after_frame_sent(spdylay_session *session)
   /* TODO handle FIN flag. */
   spdylay_frame *frame = session->aob.item->frame;
   spdylay_frame_type type = session->aob.item->frame_type;
+  if(type == SPDYLAY_DATA) {
+    if(session->callbacks.on_data_send_callback) {
+      session->callbacks.on_data_send_callback
+        (session, frame->data.flags, frame->data.stream_id,
+         session->aob.framebuflen, session->user_data);
+    }
+  } else {
+    if(session->callbacks.on_ctrl_send_callback) {
+      session->callbacks.on_ctrl_send_callback
+        (session, type, frame, session->user_data);
+    }
+  }
   switch(type) {
   case SPDYLAY_SYN_STREAM: {
     spdylay_stream *stream =