diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h
index 11df7e2..ce1a03d 100644
--- a/include/mbedtls/ecdsa.h
+++ b/include/mbedtls/ecdsa.h
@@ -279,8 +279,8 @@
  *
  * \return          \c 0 on success.
  * \return          #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid.
- * \return          #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if the signature is
- *                  valid but its actual length is less than \p siglen.
+ * \return          #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if there is a valid
+ *                  signature in \p sig, but its length is less than \p siglen.
  * \return          An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_ERR_MPI_XXX
  *                  error code on failure for any other reason.
  */