diff --git a/CHANGES b/CHANGES
index 103a74cdceda95a321e17dfb8e2d1edd4ec0173f..20c88a49b17387da00eb2a5c6d0c9687e65a4564 100644
--- a/CHANGES
+++ b/CHANGES
@@ -794,6 +794,10 @@
 
  Changes between 0.9.7g and 0.9.7h  [XX xxx XXXX]
 
+  *) Add support for smime-type MIME parameter in S/MIME messages which some
+     clients need.
+     [Steve Henson]
+
   *) New function BN_MONT_CTX_set_locked() to set montgomery parameters in
      a threadsafe manner. Modify rsa code to use new function and add calls
      to dsa and dh code (which had race conditions before).
diff --git a/crypto/pkcs7/pk7_mime.c b/crypto/pkcs7/pk7_mime.c
index d4b98fda378d35daeef59d9d9d8b9dec6853b801..134746c1864f4da4461cfb271b0b29fc6bea95aa 100644
--- a/crypto/pkcs7/pk7_mime.c
+++ b/crypto/pkcs7/pk7_mime.c
@@ -3,7 +3,7 @@
  * project.
  */
 /* ====================================================================
- * Copyright (c) 1999-2003 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -150,11 +150,12 @@ int SMIME_write_PKCS7(BIO *bio, PKCS7 *p7, BIO *data, int flags)
 {
 	char bound[33], c;
 	int i;
-	char *mime_prefix, *mime_eol;
+	char *mime_prefix, *mime_eol, *msg_type=NULL;
 	if (flags & PKCS7_NOOLDMIMETYPE)
 		mime_prefix = "application/pkcs7-";
 	else
 		mime_prefix = "application/x-pkcs7-";
+
 	if (flags & PKCS7_CRLFEOL)
 		mime_eol = "\r\n";
 	else
@@ -196,11 +197,30 @@ int SMIME_write_PKCS7(BIO *bio, PKCS7 *p7, BIO *data, int flags)
 							mime_eol, mime_eol);
 		return 1;
 	}
+
+	/* Determine smime-type header */
+
+	if (PKCS7_type_is_enveloped(p7))
+		msg_type = "enveloped-data";
+	else if (PKCS7_type_is_signed(p7))
+		{
+		/* If we have any signers it is signed-data othewise 
+		 * certs-only.
+		 */
+		STACK_OF(PKCS7_SIGNER_INFO) *sinfos;
+		sinfos = PKCS7_get_signer_info(p7);
+		if (sk_PKCS7_SIGNER_INFO_num(sinfos) > 0)
+			msg_type = "signed-data";
+		else
+			msg_type = "certs-only";
+		}
 	/* MIME headers */
 	BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 	BIO_printf(bio, "Content-Disposition: attachment;");
 	BIO_printf(bio, " filename=\"smime.p7m\"%s", mime_eol);
 	BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
+	if (msg_type)
+		BIO_printf(bio, " smime-type=%s;", msg_type);
 	BIO_printf(bio, " name=\"smime.p7m\"%s", mime_eol);
 	BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 						mime_eol, mime_eol);