diff --git a/integration-tests/nghttpx_http1_test.go b/integration-tests/nghttpx_http1_test.go
index 3114ad9c..48ac9f7c 100644
--- a/integration-tests/nghttpx_http1_test.go
+++ b/integration-tests/nghttpx_http1_test.go
@@ -209,3 +209,74 @@ func TestH1H2CrumbleCookie(t *testing.T) {
 		t.Errorf("status: %v; want %v", got, want)
 	}
 }
+
+// TestH1H2GenerateVia tests that server generates Via header field to and
+// from backend server.
+func TestH1H2GenerateVia(t *testing.T) {
+	st := newServerTester([]string{"--http2-bridge"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "1.1 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+	})
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H2GenerateVia",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "2.0 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestH1H2AppendVia tests that server adds value to existing Via
+// header field to and from backend server.
+func TestH1H2AppendVia(t *testing.T) {
+	st := newServerTester([]string{"--http2-bridge"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo, 1.1 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H2AppendVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar, 2.0 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestH1H2NoVia tests that server does not add value to existing Via
+// header field to and from backend server.
+func TestH1H2NoVia(t *testing.T) {
+	st := newServerTester([]string{"--http2-bridge", "--no-via"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H2NoVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
diff --git a/integration-tests/nghttpx_http2_test.go b/integration-tests/nghttpx_http2_test.go
index 3f5ab860..6efe9859 100644
--- a/integration-tests/nghttpx_http2_test.go
+++ b/integration-tests/nghttpx_http2_test.go
@@ -121,6 +121,77 @@ func TestH2H1StripAddXff(t *testing.T) {
 	}
 }
 
+// TestH2H1GenerateVia tests that server generates Via header field to and
+// from backend server.
+func TestH2H1GenerateVia(t *testing.T) {
+	st := newServerTester(nil, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "2.0 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+	})
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1GenerateVia",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "1.1 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1AppendVia tests that server adds value to existing Via
+// header field to and from backend server.
+func TestH2H1AppendVia(t *testing.T) {
+	st := newServerTester(nil, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo, 2.0 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1AppendVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar, 1.1 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1NoVia tests that server does not add value to existing Via
+// header field to and from backend server.
+func TestH2H1NoVia(t *testing.T) {
+	st := newServerTester([]string{"--no-via"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1NoVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
 // TestH2H1BadRequestCL tests that server rejects request whose
 // content-length header field value does not match its request body
 // size.
diff --git a/integration-tests/nghttpx_spdy_test.go b/integration-tests/nghttpx_spdy_test.go
index 6cf356d9..0b289397 100644
--- a/integration-tests/nghttpx_spdy_test.go
+++ b/integration-tests/nghttpx_spdy_test.go
@@ -99,6 +99,77 @@ func TestS3H1InvalidRequestCL(t *testing.T) {
 	}
 }
 
+// TestS3H1GenerateVia tests that server generates Via header field to and
+// from backend server.
+func TestS3H1GenerateVia(t *testing.T) {
+	st := newServerTesterTLS([]string{"--npn-list=spdy/3.1"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "1.1 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+	})
+	defer st.Close()
+
+	res, err := st.spdy(requestParam{
+		name: "TestS3H1GenerateVia",
+	})
+	if err != nil {
+		t.Fatalf("Error st.spdy() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "1.1 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestS3H1AppendVia tests that server adds value to existing Via
+// header field to and from backend server.
+func TestS3H1AppendVia(t *testing.T) {
+	st := newServerTesterTLS([]string{"--npn-list=spdy/3.1"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo, 1.1 nghttpx"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.spdy(requestParam{
+		name: "TestS3H1AppendVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.spdy() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar, 1.1 nghttpx"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
+// TestS3H1NoVia tests that server does not add value to existing Via
+// header field to and from backend server.
+func TestS3H1NoVia(t *testing.T) {
+	st := newServerTesterTLS([]string{"--npn-list=spdy/3.1", "--no-via"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("Via"), "foo"; got != want {
+			t.Errorf("Via: %v; want %v", got, want)
+		}
+		w.Header().Add("Via", "bar")
+	})
+	defer st.Close()
+
+	res, err := st.spdy(requestParam{
+		name: "TestS3H1NoVia",
+		header: []hpack.HeaderField{
+			pair("via", "foo"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.spdy() = %v", err)
+	}
+	if got, want := res.header.Get("Via"), "bar"; got != want {
+		t.Errorf("Via: %v; want %v", got, want)
+	}
+}
+
 // TestS3H2ConnectFailure tests that server handles the situation that
 // connection attempt to HTTP/2 backend failed.
 func TestS3H2ConnectFailure(t *testing.T) {
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index 41264cfb..5844d587 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -886,8 +886,13 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream) {
     }
   }
 
-  if (!get_config()->no_via) {
-    auto via = downstream->get_response_header(http2::HD_VIA);
+  auto via = downstream->get_response_header(http2::HD_VIA);
+  if (get_config()->no_via) {
+    if (via) {
+      nv[hdidx++] = "via";
+      nv[hdidx++] = via->value.c_str();
+    }
+  } else {
     if (via) {
       via_value = via->value;
       via_value += ", ";