diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index bb88ea9..41013d8 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -550,6 +550,15 @@
 #define POLARSSL_SSL_SESSION_TICKETS
 
 /**
+ * \def POLARSSL_SSL_TRUNCATED_HMAC
+ *
+ * Enable support for RFC 6066 truncated HMAC in SSL
+ *
+ * Comment this macro to disable support for truncated HMAC in SSL
+ */
+#define POLARSSL_SSL_TRUNCATED_HMAC
+
+/**
  * \def POLARSSL_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION
  *
  * If set, the X509 parser will not break-off when parsing an X509 certificate
diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index d0e71e3..8f72710 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -366,7 +366,9 @@
     unsigned char mfl_code;     /*!< MaxFragmentLength negotiated by peer */
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     int trunc_hmac;             /*!< flag for truncated hmac activation   */
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 };
 
 /*
@@ -601,7 +603,9 @@
     int disable_renegotiation;          /*!<  enable/disable renegotiation   */
     int allow_legacy_renegotiation;     /*!<  allow legacy renegotiation     */
     const int *ciphersuite_list[4];     /*!<  allowed ciphersuites / version */
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     int trunc_hmac;                     /*!<  negotiate truncated hmac?      */
+#endif
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
     int session_tickets;                /*!<  use session tickets?    */
     int ticket_lifetime;                /*!<  session ticket lifetime */
@@ -1049,6 +1053,7 @@
 int ssl_set_max_frag_len( ssl_context *ssl, unsigned char mfl_code );
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 /**
  * \brief          Activate negotiation of truncated HMAC (Client only)
  *                 (Default: SSL_TRUNC_HMAC_ENABLED)
@@ -1061,6 +1066,7 @@
  *                 POLARSSL_ERR_SSL_BAD_INPUT_DATA if used server-side
  */
 int ssl_set_truncated_hmac( ssl_context *ssl, int truncate );
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 /**
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 772b2c9..a80a769 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -302,6 +302,7 @@
 }
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
                                           unsigned char *buf, size_t *olen )
 {
@@ -323,6 +324,7 @@
 
     *olen = 4;
 }
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static void ssl_write_session_ticket_ext( ssl_context *ssl,
@@ -553,8 +555,10 @@
     ext_len += olen;
 #endif
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
+#endif
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
     ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
@@ -645,6 +649,7 @@
 }
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -661,6 +666,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static int ssl_parse_session_ticket_ext( ssl_context *ssl,
@@ -910,6 +916,7 @@
             break;
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
         case TLS_EXT_TRUNCATED_HMAC:
             SSL_DEBUG_MSG( 3, ( "found truncated_hmac extension" ) );
 
@@ -920,6 +927,7 @@
             }
 
             break;
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
         case TLS_EXT_SESSION_TICKET:
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index ff0e9d1..2b6f06f 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -581,6 +581,7 @@
 }
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -597,6 +598,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static int ssl_parse_session_ticket_ext( ssl_context *ssl,
@@ -1186,6 +1188,7 @@
             break;
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
         case TLS_EXT_TRUNCATED_HMAC:
             SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
 
@@ -1193,6 +1196,7 @@
             if( ret != 0 )
                 return( ret );
             break;
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
         case TLS_EXT_SESSION_TICKET:
@@ -1313,6 +1317,7 @@
     return( 0 );
 }
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
                                           unsigned char *buf,
                                           size_t *olen )
@@ -1335,6 +1340,7 @@
 
     *olen = 4;
 }
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static void ssl_write_session_ticket_ext( ssl_context *ssl,
@@ -1562,8 +1568,10 @@
     ext_len += olen;
 #endif
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
+#endif
 
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
     ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 1281bc8..039b536 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -516,6 +516,7 @@
 
             transform->maclen = md_get_size( md_info );
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
             /*
              * If HMAC is to be truncated, we shall keep the leftmost bytes,
              * (rfc 6066 page 13 or rfc 2104 section 4),
@@ -523,6 +524,7 @@
              */
             if( session->trunc_hmac == SSL_TRUNC_HMAC_ENABLED )
                 transform->maclen = SSL_TRUNCATED_HMAC_LEN;
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
         }
 
         transform->keylen = cipher_info->key_length;
@@ -3255,6 +3257,7 @@
 }
 #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
 int ssl_set_truncated_hmac( ssl_context *ssl, int truncate )
 {
     if( ssl->endpoint != SSL_IS_CLIENT )
@@ -3264,6 +3267,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
 void ssl_set_renegotiation( ssl_context *ssl, int renegotiation )
 {
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index a422bf4..7dd11b9 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -185,6 +185,13 @@
 #define USAGE_TICKETS ""
 #endif /* POLARSSL_SSL_SESSION_TICKETS */
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
+#define USAGE_TRUNC_HMAC                                    \
+    "    trunc_hmac=%%d       default: 0 (disabled)\n"
+#else
+#define USAGE_TRUNC_HMAC ""
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
+
 #if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 #define USAGE_MAX_FRAG_LEN                                      \
     "    max_frag_len=%%d     default: 16384 (tls default)\n"   \
@@ -213,7 +220,7 @@
     "    auth_mode=%%s        default: \"optional\"\n"          \
     "                        options: none, optional, required\n" \
     USAGE_MAX_FRAG_LEN                                      \
-    "    trunc_hmac=%%d       default: 0 (disabled)\n"      \
+    USAGE_TRUNC_HMAC                                        \
     USAGE_PSK                                               \
     "\n"                                                    \
     "    force_ciphersuite=<name>    default: all enabled\n"\
@@ -682,8 +689,10 @@
     ssl_set_max_frag_len( &ssl, opt.mfl_code );
 #endif
 
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     if( opt.trunc_hmac != 0 )
         ssl_set_truncated_hmac( &ssl, SSL_TRUNC_HMAC_ENABLED );
+#endif
 
     ssl_set_rng( &ssl, ctr_drbg_random, &ctr_drbg );
     ssl_set_dbg( &ssl, my_debug, stdout );