diff --git a/src/poly.c b/src/poly.c
index 01dade9..8625a13 100644
--- a/src/poly.c
+++ b/src/poly.c
@@ -66,7 +66,7 @@ void init_polynom(pb_poly *new_poly, mp_int *chara)
  * @param chara the characteristic
  * @param size the size of the polynomial
  */
-void init_polynom_size(pb_poly *new_poly, mp_int *chara, int size)
+void init_polynom_size(pb_poly *new_poly, mp_int *chara, size_t size)
 {
 	int result;
 	if ((result = pb_init_size(new_poly, chara, size)) != MP_OKAY) {
diff --git a/src/poly.h b/src/poly.h
index 6bca69d..7b534ba 100644
--- a/src/poly.h
+++ b/src/poly.h
@@ -31,7 +31,7 @@ void init_integer(mp_int *new_int);
 
 void init_polynom(pb_poly *new_poly, mp_int *chara);
 
-void init_polynom_size(pb_poly *new_poly, mp_int *chara, int size);
+void init_polynom_size(pb_poly *new_poly, mp_int *chara, size_t size);
 
 void delete_polynom(pb_poly *new_poly);