diff --git a/include/mbedtls/x509.h b/include/mbedtls/x509.h
index d6db9c6..9ae825c 100644
--- a/include/mbedtls/x509.h
+++ b/include/mbedtls/x509.h
@@ -269,6 +269,8 @@
  */
 int mbedtls_x509_time_is_future( const mbedtls_x509_time *from );
 
+#if defined(MBEDTLS_SELF_TEST)
+
 /**
  * \brief          Checkup routine
  *
@@ -276,6 +278,8 @@
  */
 int mbedtls_x509_self_test( int verbose );
 
+#endif /* MBEDTLS_SELF_TEST */
+
 /*
  * Internal module functions. You probably do not want to use these unless you
  * know you do.