diff --git a/include/polarssl/base64.h b/include/polarssl/base64.h
index 883215dd4..fb0d753a2 100644
--- a/include/polarssl/base64.h
+++ b/include/polarssl/base64.h
@@ -63,8 +63,8 @@ int base64_encode( unsigned char *dst, size_t *dlen,
  * \param slen     amount of data to be decoded
  *
  * \return         0 if successful, POLARSSL_ERR_BASE64_BUFFER_TOO_SMALL, or
- *                 POLARSSL_ERR_BASE64_INVALID_DATA if the input data is not
- *                 correct. *dlen is always updated to reflect the amount
+ *                 POLARSSL_ERR_BASE64_INVALID_CHARACTER if the input data is
+ *                 not correct. *dlen is always updated to reflect the amount
  *                 of data that has (or would have) been written.
  *
  * \note           Call this function with *dlen = 0 to obtain the