diff --git a/library/bignum.c b/library/bignum.c
index f1cf80885..f07f746d4 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -951,7 +951,7 @@ static unsigned ct_lt_mpi_uint( const mbedtls_mpi_uint x,
 
     ret = ret >> ( biL - 1 );
 
-    return ret;
+    return (unsigned) ret;
 }
 
 /*