diff --git a/src/asio_client_session.cc b/src/asio_client_session.cc
index bc835c38..5762c4c5 100644
--- a/src/asio_client_session.cc
+++ b/src/asio_client_session.cc
@@ -39,15 +39,33 @@ using boost::asio::ip::tcp;
 
 session::session(boost::asio::io_service &io_service, const std::string &host,
                  const std::string &service)
-    : impl_(std::make_shared<session_tcp_impl>(io_service, host, service)) {
+    : impl_(std::make_shared<session_tcp_impl>(
+          io_service, host, service, boost::posix_time::seconds(60))) {
+  impl_->start_resolve(host, service);
+}
+
+session::session(boost::asio::io_service &io_service, const std::string &host,
+                 const std::string &service,
+                 const boost::posix_time::time_duration &connect_timeout)
+    : impl_(std::make_shared<session_tcp_impl>(io_service, host, service,
+                                               connect_timeout)) {
   impl_->start_resolve(host, service);
 }
 
 session::session(boost::asio::io_service &io_service,
                  boost::asio::ssl::context &tls_ctx, const std::string &host,
                  const std::string &service)
+    : impl_(std::make_shared<session_tls_impl>(
+          io_service, tls_ctx, host, service, boost::posix_time::seconds(60))) {
+  impl_->start_resolve(host, service);
+}
+
+session::session(boost::asio::io_service &io_service,
+                 boost::asio::ssl::context &tls_ctx, const std::string &host,
+                 const std::string &service,
+                 const boost::posix_time::time_duration &connect_timeout)
     : impl_(std::make_shared<session_tls_impl>(io_service, tls_ctx, host,
-                                               service)) {
+                                               service, connect_timeout)) {
   impl_->start_resolve(host, service);
 }
 
@@ -97,10 +115,6 @@ const request *session::submit(boost::system::error_code &ec,
   return impl_->submit(ec, method, uri, std::move(cb), std::move(h));
 }
 
-void session::connect_timeout(const boost::posix_time::time_duration &t) {
-  impl_->connect_timeout(t);
-}
-
 void session::read_timeout(const boost::posix_time::time_duration &t) {
   impl_->read_timeout(t);
 }
diff --git a/src/asio_client_session_impl.cc b/src/asio_client_session_impl.cc
index fa275f8e..2ea65cd1 100644
--- a/src/asio_client_session_impl.cc
+++ b/src/asio_client_session_impl.cc
@@ -38,12 +38,14 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace client {
 
-session_impl::session_impl(boost::asio::io_service &io_service)
+session_impl::session_impl(
+    boost::asio::io_service &io_service,
+    const boost::posix_time::time_duration &connect_timeout)
     : wblen_(0),
       io_service_(io_service),
       resolver_(io_service),
       deadline_(io_service),
-      connect_timeout_(boost::posix_time::seconds(60)),
+      connect_timeout_(connect_timeout),
       read_timeout_(boost::posix_time::seconds(60)),
       session_(nullptr),
       data_pending_(nullptr),
@@ -705,9 +707,7 @@ void session_impl::stop() {
   stopped_ = true;
 }
 
-void session_impl::connect_timeout(const boost::posix_time::time_duration &t) {
-  connect_timeout_ = t;
-}
+bool session_impl::stopped() const { return stopped_; }
 
 void session_impl::read_timeout(const boost::posix_time::time_duration &t) {
   read_timeout_ = t;
diff --git a/src/asio_client_session_impl.h b/src/asio_client_session_impl.h
index 5e936c37..d62d252a 100644
--- a/src/asio_client_session_impl.h
+++ b/src/asio_client_session_impl.h
@@ -43,7 +43,8 @@ using boost::asio::ip::tcp;
 
 class session_impl : public std::enable_shared_from_this<session_impl> {
 public:
-  session_impl(boost::asio::io_service &io_service);
+  session_impl(boost::asio::io_service &io_service,
+               const boost::posix_time::time_duration &connect_timeout);
   virtual ~session_impl();
 
   void start_resolve(const std::string &host, const std::string &service);
@@ -91,10 +92,10 @@ public:
   void do_read();
   void do_write();
 
-  void connect_timeout(const boost::posix_time::time_duration &t);
   void read_timeout(const boost::posix_time::time_duration &t);
 
   void stop();
+  bool stopped() const;
 
 protected:
   boost::array<uint8_t, 8_k> rb_;
diff --git a/src/asio_client_session_tcp_impl.cc b/src/asio_client_session_tcp_impl.cc
index 478f1c16..398ce767 100644
--- a/src/asio_client_session_tcp_impl.cc
+++ b/src/asio_client_session_tcp_impl.cc
@@ -28,10 +28,11 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace client {
 
-session_tcp_impl::session_tcp_impl(boost::asio::io_service &io_service,
-                                   const std::string &host,
-                                   const std::string &service)
-    : session_impl(io_service), socket_(io_service) {}
+session_tcp_impl::session_tcp_impl(
+    boost::asio::io_service &io_service, const std::string &host,
+    const std::string &service,
+    const boost::posix_time::time_duration &connect_timeout)
+    : session_impl(io_service, connect_timeout), socket_(io_service) {}
 
 session_tcp_impl::~session_tcp_impl() {}
 
@@ -39,6 +40,10 @@ void session_tcp_impl::start_connect(tcp::resolver::iterator endpoint_it) {
   boost::asio::async_connect(socket_, endpoint_it,
                              [this](const boost::system::error_code &ec,
                                     tcp::resolver::iterator endpoint_it) {
+                               if (stopped()) {
+                                 return;
+                               }
+
                                if (ec) {
                                  not_connected(ec);
                                  return;
diff --git a/src/asio_client_session_tcp_impl.h b/src/asio_client_session_tcp_impl.h
index 6138828b..70ede36a 100644
--- a/src/asio_client_session_tcp_impl.h
+++ b/src/asio_client_session_tcp_impl.h
@@ -38,7 +38,8 @@ using boost::asio::ip::tcp;
 class session_tcp_impl : public session_impl {
 public:
   session_tcp_impl(boost::asio::io_service &io_service, const std::string &host,
-                   const std::string &service);
+                   const std::string &service,
+                   const boost::posix_time::time_duration &connect_timeout);
   virtual ~session_tcp_impl();
 
   virtual void start_connect(tcp::resolver::iterator endpoint_it);
diff --git a/src/asio_client_session_tls_impl.cc b/src/asio_client_session_tls_impl.cc
index 486c52d7..e37d7b02 100644
--- a/src/asio_client_session_tls_impl.cc
+++ b/src/asio_client_session_tls_impl.cc
@@ -29,11 +29,11 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace client {
 
-session_tls_impl::session_tls_impl(boost::asio::io_service &io_service,
-                                   boost::asio::ssl::context &tls_ctx,
-                                   const std::string &host,
-                                   const std::string &service)
-    : session_impl(io_service), socket_(io_service, tls_ctx) {
+session_tls_impl::session_tls_impl(
+    boost::asio::io_service &io_service, boost::asio::ssl::context &tls_ctx,
+    const std::string &host, const std::string &service,
+    const boost::posix_time::time_duration &connect_timeout)
+    : session_impl(io_service, connect_timeout), socket_(io_service, tls_ctx) {
   // this callback setting is no effect is
   // ssl::context::set_verify_mode(boost::asio::ssl::verify_peer) is
   // not used, which is what we want.
@@ -46,6 +46,10 @@ void session_tls_impl::start_connect(tcp::resolver::iterator endpoint_it) {
   boost::asio::async_connect(
       socket(), endpoint_it, [this](const boost::system::error_code &ec,
                                     tcp::resolver::iterator endpoint_it) {
+        if (stopped()) {
+          return;
+        }
+
         if (ec) {
           not_connected(ec);
           return;
@@ -54,6 +58,10 @@ void session_tls_impl::start_connect(tcp::resolver::iterator endpoint_it) {
         socket_.async_handshake(
             boost::asio::ssl::stream_base::client,
             [this, endpoint_it](const boost::system::error_code &ec) {
+              if (stopped()) {
+                return;
+              }
+
               if (ec) {
                 not_connected(ec);
                 return;
diff --git a/src/asio_client_session_tls_impl.h b/src/asio_client_session_tls_impl.h
index 484e3d45..51106541 100644
--- a/src/asio_client_session_tls_impl.h
+++ b/src/asio_client_session_tls_impl.h
@@ -41,7 +41,8 @@ class session_tls_impl : public session_impl {
 public:
   session_tls_impl(boost::asio::io_service &io_service,
                    boost::asio::ssl::context &tls_ctx, const std::string &host,
-                   const std::string &service);
+                   const std::string &service,
+                   const boost::posix_time::time_duration &connect_timeout);
   virtual ~session_tls_impl();
 
   virtual void start_connect(tcp::resolver::iterator endpoint_it);
diff --git a/src/includes/nghttp2/asio_http2_client.h b/src/includes/nghttp2/asio_http2_client.h
index 55ef9f68..c3662e2e 100644
--- a/src/includes/nghttp2/asio_http2_client.h
+++ b/src/includes/nghttp2/asio_http2_client.h
@@ -123,15 +123,33 @@ class session_impl;
 class session {
 public:
   // Starts HTTP/2 session by connecting to |host| and |service|
-  // (e.g., "80") using clear text TCP connection.
+  // (e.g., "80") using clear text TCP connection with connect timeout
+  // 60 seconds.
   session(boost::asio::io_service &io_service, const std::string &host,
           const std::string &service);
 
   // Starts HTTP/2 session by connecting to |host| and |service|
-  // (e.g., "443") using encrypted SSL/TLS connection.
+  // (e.g., "80") using clear text TCP connection with given connect
+  // timeout.
+  session(boost::asio::io_service &io_service, const std::string &host,
+          const std::string &service,
+          const boost::posix_time::time_duration &connect_timeout);
+
+  // Starts HTTP/2 session by connecting to |host| and |service|
+  // (e.g., "443") using encrypted SSL/TLS connection with connect
+  // timeout 60 seconds.
   session(boost::asio::io_service &io_service,
           boost::asio::ssl::context &tls_context, const std::string &host,
           const std::string &service);
+
+  // Starts HTTP/2 session by connecting to |host| and |service|
+  // (e.g., "443") using encrypted SSL/TLS connection with given
+  // connect timeout.
+  session(boost::asio::io_service &io_service,
+          boost::asio::ssl::context &tls_context, const std::string &host,
+          const std::string &service,
+          const boost::posix_time::time_duration &connect_timeout);
+
   ~session();
 
   session(session &&other) noexcept;
@@ -144,9 +162,6 @@ public:
   // and session is terminated.
   void on_error(error_cb cb) const;
 
-  // Sets connect timeout, which defaults to 60 seconds.
-  void connect_timeout(const boost::posix_time::time_duration &t);
-
   // Sets read timeout, which defaults to 60 seconds.
   void read_timeout(const boost::posix_time::time_duration &t);