diff --git a/core/AmSipHeaders.h b/core/AmSipHeaders.h
index dc22b9c1..dd240e70 100644
--- a/core/AmSipHeaders.h
+++ b/core/AmSipHeaders.h
@@ -20,6 +20,7 @@
 #define SIP_HDR_USER_AGENT      "User-Agent"
 #define SIP_HDR_MAX_FORWARDS    "Max-Forwards"
 #define SIP_HDR_P_ASSERTED_IDENTITY "P-Asserted-Identity"
+#define SIP_HDR_P_PREFERRED_IDENTITY "P-Preferred-Identity"
 #define SIP_HDR_REFER_TO        "Refer-To"
 #define SIP_HDR_EXPIRES         "Expires"
 #define SIP_HDR_SESSION_EXPIRES "Session-Expires"