diff --git a/mime.go b/mime.go
index a60fb2d..83b3555 100644
--- a/mime.go
+++ b/mime.go
@@ -97,9 +97,11 @@ func (email Email) WriteMime(dest io.Writer) error {
 	dest.Write([]byte("From: " + email.From + "\r\n"))
 	dest.Write([]byte("To: " + email.To + "\r\n"))
 	if email.ReturnPath != "" {
-		dest.Write([]byte("Return-Path: <" + email.ReturnPath + ">\r\n"))
-	} else {
-		dest.Write([]byte("Return-Path: <" + email.From + ">\r\n"))
+		if email.ReturnPath[0] == "<" {
+			dest.Write([]byte("Return-Path: " + email.ReturnPath + "\r\n"))
+		} else {
+			dest.Write([]byte("Return-Path: <" + email.ReturnPath + ">\r\n"))
+		}
 	}
 	if email.ReplyTo != "" {
 		dest.Write([]byte("Reply-To: " + email.ReplyTo + "\r\n"))