diff --git a/src/HttpServer.cc b/src/HttpServer.cc
index 048bc493..4ed54289 100644
--- a/src/HttpServer.cc
+++ b/src/HttpServer.cc
@@ -315,7 +315,8 @@ int Http2Handler::on_read()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(bev_)) == 0) {
       rv = -1;
     }
   }
@@ -331,7 +332,8 @@ int Http2Handler::on_write()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(bev_)) == 0) {
       rv = -1;
     }
   }
diff --git a/src/nghttp.cc b/src/nghttp.cc
index 93e312e9..6fbc8a44 100644
--- a/src/nghttp.cc
+++ b/src/nghttp.cc
@@ -508,7 +508,8 @@ struct HttpClient {
     }
     if(rv == 0) {
       if(nghttp2_session_want_read(session) == 0 &&
-         nghttp2_session_want_write(session) == 0) {
+         nghttp2_session_want_write(session) == 0 &&
+         evbuffer_get_length(bufferevent_get_output(bev)) == 0) {
         rv = -1;
       }
     }
@@ -524,7 +525,8 @@ struct HttpClient {
     }
     if(rv == 0) {
       if(nghttp2_session_want_read(session) == 0 &&
-         nghttp2_session_want_write(session) == 0) {
+         nghttp2_session_want_write(session) == 0 &&
+         evbuffer_get_length(bufferevent_get_output(bev)) == 0) {
         rv = -1;
       }
     }
diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index 44554e98..a0fa6a42 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -403,7 +403,8 @@ int Http2Upstream::on_read()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(handler_->get_bev())) == 0) {
       if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }
@@ -428,7 +429,8 @@ int Http2Upstream::send()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(handler_->get_bev())) == 0) {
       if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }
diff --git a/src/shrpx_spdy_session.cc b/src/shrpx_spdy_session.cc
index 0f0f0110..a07d1f3c 100644
--- a/src/shrpx_spdy_session.cc
+++ b/src/shrpx_spdy_session.cc
@@ -1109,7 +1109,8 @@ int SpdySession::on_read()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(bev_)) == 0) {
       if(LOG_ENABLED(INFO)) {
         SSLOG(INFO, this) << "No more read/write for this session";
       }
@@ -1133,7 +1134,8 @@ int SpdySession::send()
   }
   if(rv == 0) {
     if(nghttp2_session_want_read(session_) == 0 &&
-       nghttp2_session_want_write(session_) == 0) {
+       nghttp2_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(bev_)) == 0) {
       if(LOG_ENABLED(INFO)) {
         SSLOG(INFO, this) << "No more read/write for this session";
       }
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index 1cb76314..e860523a 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -407,7 +407,8 @@ int SpdyUpstream::on_read()
   }
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
-       spdylay_session_want_write(session_) == 0) {
+       spdylay_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(handler_->get_bev())) == 0) {
       if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }
@@ -432,7 +433,8 @@ int SpdyUpstream::send()
   }
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
-       spdylay_session_want_write(session_) == 0) {
+       spdylay_session_want_write(session_) == 0 &&
+       evbuffer_get_length(bufferevent_get_output(handler_->get_bev())) == 0) {
       if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }