diff --git a/examples/shrpx_downstream.cc b/examples/shrpx_downstream.cc
index 9411f050..be4d6d94 100644
--- a/examples/shrpx_downstream.cc
+++ b/examples/shrpx_downstream.cc
@@ -49,6 +49,7 @@ Downstream::Downstream(Upstream *upstream, int stream_id, int priority)
     request_minor_(1),
     chunked_request_(false),
     request_connection_close_(false),
+    request_expect_100_continue_(false),
     response_state_(INITIAL),
     response_http_status_(0),
     response_major_(1),
@@ -111,15 +112,31 @@ void Downstream::force_resume_read()
   ioctrl_.force_resume_read();
 }
 
+namespace {
+void check_header_field(bool *result, const Headers::value_type &item,
+                        const char *name, const char *value)
+{
+  if(util::strieq(item.first.c_str(), name)) {
+    if(util::strifind(item.second.c_str(), value)) {
+      *result = true;
+    }
+  }
+}
+} // namespace
+
 namespace {
 void check_transfer_encoding_chunked(bool *chunked,
                                      const Headers::value_type &item)
 {
-  if(util::strieq(item.first.c_str(), "transfer-encoding")) {
-    if(util::strifind(item.second.c_str(), "chunked")) {
-      *chunked = true;
-    }
-  }
+  return check_header_field(chunked, item, "transfer-encoding", "chunked");
+}
+} // namespace
+
+namespace {
+void check_expect_100_continue(bool *res,
+                               const Headers::value_type& item)
+{
+  return check_header_field(res, item, "expect", "100-continue");
 }
 } // namespace
 
@@ -136,7 +153,7 @@ void check_connection_close(bool *connection_close,
   }
 }
 } // namespace
-  
+
 void Downstream::add_request_header(const std::string& name,
                                     const std::string& value)
 {
@@ -148,6 +165,7 @@ void Downstream::set_last_request_header_value(const std::string& value)
   Headers::value_type &item = request_headers_.back();
   item.second = value;
   check_transfer_encoding_chunked(&chunked_request_, item);
+  check_expect_100_continue(&request_expect_100_continue_, item);
   check_connection_close(&request_connection_close_, item);
 }
 
@@ -216,6 +234,11 @@ void Downstream::set_request_connection_close(bool f)
   request_connection_close_ = f;
 }
 
+bool Downstream::get_expect_100_continue() const
+{
+  return request_expect_100_continue_;
+}
+
 namespace {
 const size_t DOWNSTREAM_OUTPUT_UPPER_THRES = 64*1024;
 } // namespace
@@ -255,6 +278,10 @@ int Downstream::push_request_headers()
     if(util::strieq((*i).first.c_str(), "host")) {
       continue;
     }
+    if(util::strieq((*i).first.c_str(), "expect") &&
+       util::strifind((*i).second.c_str(), "100-continue")) {
+      continue;
+    }
     hdrs += (*i).first;
     hdrs += ": ";
     hdrs += (*i).second;
diff --git a/examples/shrpx_downstream.h b/examples/shrpx_downstream.h
index 5fd7b29a..fb1605e1 100644
--- a/examples/shrpx_downstream.h
+++ b/examples/shrpx_downstream.h
@@ -80,6 +80,7 @@ public:
   bool get_chunked_request() const;
   bool get_request_connection_close() const;
   void set_request_connection_close(bool f);
+  bool get_expect_100_continue() const;
   int push_upload_data_chunk(const uint8_t *data, size_t datalen);
   int end_upload_data();
   enum {
@@ -122,6 +123,7 @@ private:
   int request_minor_;
   bool chunked_request_;
   bool request_connection_close_;
+  bool request_expect_100_continue_;
   Headers request_headers_;
 
   int response_state_;
diff --git a/examples/shrpx_https_upstream.cc b/examples/shrpx_https_upstream.cc
index a0898ab7..cf77408a 100644
--- a/examples/shrpx_https_upstream.cc
+++ b/examples/shrpx_https_upstream.cc
@@ -161,6 +161,12 @@ int htp_hdrs_completecb(htparser *htp)
   DownstreamConnection *dconn;
   dconn = upstream->get_client_handler()->get_downstream_connection();
 
+  if(downstream->get_expect_100_continue()) {
+    static const char reply_100[] = "HTTP/1.1 100 Continue\r\n\r\n";
+    bufferevent_write(upstream->get_client_handler()->get_bev(),
+                      reply_100, sizeof(reply_100)-1);
+  }
+
   int rv =  dconn->attach_downstream(downstream);
   if(rv != 0) {
     downstream->set_request_state(Downstream::CONNECT_FAIL);