diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 9964607..c7b1225 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -147,6 +147,7 @@
 #define POLARSSL_ERR_SSL_COUNTER_WRAPPING                  -0x6B80  /**< A counter would wrap (eg, too many messages exchanged). */
 #define POLARSSL_ERR_SSL_WAITING_SERVER_HELLO_RENEGO       -0x6B00  /**< Unexpected message at ServerHello in renegotiation. */
 #define POLARSSL_ERR_SSL_HELLO_VERIFY_REQUIRED             -0x6A80  /**< DTLS client must retry for hello verification */
+#define POLARSSL_ERR_SSL_BUFFER_TOO_SMALL                  -0x6A00  /**< A buffer is too small to receive or write a message */
 
 /*
  * Various constants