diff --git a/actix-http/src/client/h1proto.rs b/actix-http/src/client/h1proto.rs
index 5fec9c4f1..3a8b119d3 100644
--- a/actix-http/src/client/h1proto.rs
+++ b/actix-http/src/client/h1proto.rs
@@ -1,12 +1,14 @@
+use std::io::Write;
 use std::{io, time};
 
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
-use bytes::Bytes;
+use bytes::{BufMut, Bytes, BytesMut};
 use futures::future::{ok, Either};
 use futures::{Async, Future, Poll, Sink, Stream};
 
 use crate::error::PayloadError;
 use crate::h1;
+use crate::http::header::{IntoHeaderValue, HOST};
 use crate::message::{RequestHead, ResponseHead};
 use crate::payload::{Payload, PayloadStream};
 
@@ -17,7 +19,7 @@ use crate::body::{BodySize, MessageBody};
 
 pub(crate) fn send_request<T, B>(
     io: T,
-    head: RequestHead,
+    mut head: RequestHead,
     body: B,
     created: time::Instant,
     pool: Option<Acquired<T>>,
@@ -26,6 +28,27 @@ where
     T: AsyncRead + AsyncWrite + 'static,
     B: MessageBody,
 {
+    // set request host header
+    if !head.headers.contains_key(HOST) {
+        if let Some(host) = head.uri.host() {
+            let mut wrt = BytesMut::with_capacity(host.len() + 5).writer();
+
+            let _ = match head.uri.port_u16() {
+                None | Some(80) | Some(443) => write!(wrt, "{}", host),
+                Some(port) => write!(wrt, "{}:{}", host, port),
+            };
+
+            match wrt.get_mut().take().freeze().try_into() {
+                Ok(value) => {
+                    head.headers.insert(HOST, value);
+                }
+                Err(e) => {
+                    log::error!("Can not set HOST header {}", e);
+                }
+            }
+        }
+    }
+
     let io = H1Connection {
         created,
         pool,