diff --git a/integration-tests/nghttpx_http1_test.go b/integration-tests/nghttpx_http1_test.go
index cbddc13a..dd29f262 100644
--- a/integration-tests/nghttpx_http1_test.go
+++ b/integration-tests/nghttpx_http1_test.go
@@ -9,6 +9,7 @@ import (
 	"golang.org/x/net/websocket"
 	"io"
 	"net/http"
+	"regexp"
 	"syscall"
 	"testing"
 	"time"
@@ -125,6 +126,54 @@ Content-Length: 0
 // 	}
 // }
 
+// TestH1H1AffinityCookie tests that affinity cookie is sent back in
+// cleartext http.
+func TestH1H1AffinityCookie(t *testing.T) {
+	st := newServerTester([]string{"--affinity-cookie"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1AffinityCookie",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	const pattern = `affinity=[0-9a-f]{8}; Path=/foo/bar`
+	validCookie := regexp.MustCompile(pattern)
+	if got := res.header.Get("Set-Cookie"); !validCookie.MatchString(got) {
+		t.Errorf("Set-Cookie: %v; want pattern %v", got, pattern)
+	}
+}
+
+// TestH1H1AffinityCookieTLS tests that affinity cookie is sent back
+// in https.
+func TestH1H1AffinityCookieTLS(t *testing.T) {
+	st := newServerTesterTLS([]string{"--alpn-h1", "--affinity-cookie"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1AffinityCookieTLS",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	const pattern = `affinity=[0-9a-f]{8}; Path=/foo/bar; Secure`
+	validCookie := regexp.MustCompile(pattern)
+	if got := res.header.Get("Set-Cookie"); !validCookie.MatchString(got) {
+		t.Errorf("Set-Cookie: %v; want pattern %v", got, pattern)
+	}
+}
+
 // TestH1H1GracefulShutdown tests graceful shutdown.
 func TestH1H1GracefulShutdown(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
diff --git a/integration-tests/nghttpx_http2_test.go b/integration-tests/nghttpx_http2_test.go
index 9ec1c264..93fc25d7 100644
--- a/integration-tests/nghttpx_http2_test.go
+++ b/integration-tests/nghttpx_http2_test.go
@@ -1705,6 +1705,55 @@ func TestH2H1Code204TE(t *testing.T) {
 	}
 }
 
+// TestH2H1AffinityCookie tests that affinity cookie is sent back in
+// cleartext http.
+func TestH2H1AffinityCookie(t *testing.T) {
+	st := newServerTester([]string{"--affinity-cookie"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1AffinityCookie",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	const pattern = `affinity=[0-9a-f]{8}; Path=/foo/bar`
+	validCookie := regexp.MustCompile(pattern)
+	if got := res.header.Get("Set-Cookie"); !validCookie.MatchString(got) {
+		t.Errorf("Set-Cookie: %v; want pattern %v", got, pattern)
+	}
+}
+
+// TestH2H1AffinityCookieTLS tests that affinity cookie is sent back
+// in https.
+func TestH2H1AffinityCookieTLS(t *testing.T) {
+	st := newServerTesterTLS([]string{"--affinity-cookie"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name:   "TestH2H1AffinityCookieTLS",
+		scheme: "https",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+
+	const pattern = `affinity=[0-9a-f]{8}; Path=/foo/bar; Secure`
+	validCookie := regexp.MustCompile(pattern)
+	if got := res.header.Get("Set-Cookie"); !validCookie.MatchString(got) {
+		t.Errorf("Set-Cookie: %v; want pattern %v", got, pattern)
+	}
+}
+
 // TestH2H1GracefulShutdown tests graceful shutdown.
 func TestH2H1GracefulShutdown(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
diff --git a/integration-tests/server_tester.go b/integration-tests/server_tester.go
index dd4c341f..d145519d 100644
--- a/integration-tests/server_tester.go
+++ b/integration-tests/server_tester.go
@@ -101,7 +101,7 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 
 	args := []string{}
 
-	var backendTLS, dns, externalDNS, acceptProxyProtocol, redirectIfNotTLS bool
+	var backendTLS, dns, externalDNS, acceptProxyProtocol, redirectIfNotTLS, affinityCookie, alpnH1 bool
 
 	for _, k := range src_args {
 		switch k {
@@ -116,6 +116,10 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 			acceptProxyProtocol = true
 		case "--redirect-if-not-tls":
 			redirectIfNotTLS = true
+		case "--affinity-cookie":
+			affinityCookie = true
+		case "--alpn-h1":
+			alpnH1 = true
 		default:
 			args = append(args, k)
 		}
@@ -168,6 +172,10 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 		b += ";redirect-if-not-tls"
 	}
 
+	if affinityCookie {
+		b += ";affinity=cookie;affinity-cookie-name=affinity;affinity-cookie-path=/foo/bar"
+	}
+
 	noTLS := ";no-tls"
 	if frontendTLS {
 		noTLS = ""
@@ -218,7 +226,11 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 				tlsConfig = clientConfig
 			}
 			tlsConfig.InsecureSkipVerify = true
-			tlsConfig.NextProtos = []string{"h2", "spdy/3.1"}
+			if alpnH1 {
+				tlsConfig.NextProtos = []string{"http/1.1"}
+			} else {
+				tlsConfig.NextProtos = []string{"h2", "spdy/3.1"}
+			}
 			conn, err = tls.Dial("tcp", authority, tlsConfig)
 		} else {
 			conn, err = net.Dial("tcp", authority)