diff --git a/interop/client/main.go b/interop/client/main.go
index 9a4d40d3..649bc616 100644
--- a/interop/client/main.go
+++ b/interop/client/main.go
@@ -85,6 +85,8 @@ func runTestcase(testcase string) error {
 
 	switch testcase {
 	case "handshake", "transfer", "retry":
+	case "chacha20":
+		tlsConf.CipherSuites = []uint16{tls.TLS_CHACHA20_POLY1305_SHA256}
 	case "multiconnect":
 		return runMultiConnectTest(r, urls)
 	case "versionnegotiation":