diff --git a/include/mbedtls/x509_csr.h b/include/mbedtls/x509_csr.h
index 7ae7d22..b52ffff 100644
--- a/include/mbedtls/x509_csr.h
+++ b/include/mbedtls/x509_csr.h
@@ -273,7 +273,7 @@
  * \param f_rng     RNG function (for signature, see note)
  * \param p_rng     RNG parameter
  *
- * \return          0 successful, or a specific error code
+ * \return          0 if successful, or a specific error code
  *
  * \note            f_rng may be NULL if RSA is used for signature and the
  *                  signature is made offline (otherwise f_rng is desirable