diff --git a/server.go b/server.go
index c4e05c3..5421720 100644
--- a/server.go
+++ b/server.go
@@ -91,8 +91,8 @@ func parseFlags() options {
 }
 
 func Listeners() []*net.TCPListener {
-	defer os.Unsetenv("LISTEN_PID")
-	defer os.Unsetenv("LISTEN_FDS")
+	defer unsetenv("LISTEN_PID")
+	defer unsetenv("LISTEN_FDS")
 
 	pid, err := strconv.Atoi(os.Getenv("LISTEN_PID"))
 	if err != nil || pid != os.Getpid() {
diff --git a/unsetenv.go b/unsetenv.go
new file mode 100644
index 0000000..0c89d5e
--- /dev/null
+++ b/unsetenv.go
@@ -0,0 +1,9 @@
+// +build go1.4
+
+package main
+
+import "os"
+
+func unsetenv(key string) {
+	os.Unsetenv(key)
+}
diff --git a/unsetenv_13.go b/unsetenv_13.go
new file mode 100644
index 0000000..5245409
--- /dev/null
+++ b/unsetenv_13.go
@@ -0,0 +1,9 @@
+// +build !go1.4
+
+package main
+
+import "os"
+
+func unsetenv(key string) {
+	os.Setenv(key, "")
+}