diff --git a/include/tinycrypt/ecc.h b/include/tinycrypt/ecc.h
index 3d60267..e016c69 100644
--- a/include/tinycrypt/ecc.h
+++ b/include/tinycrypt/ecc.h
@@ -386,7 +386,7 @@
  * @warning Currently only designed to work for curve_p or curve_n.
  */
 void uECC_vli_mmod(uECC_word_t *result, uECC_word_t *product,
-		   const uECC_word_t *mod, wordcount_t num_words);
+		   const uECC_word_t *mod);
 
 /*
  * @brief Computes modular product (using curve->mmod_fast)