diff --git a/src/lib.rs b/src/lib.rs
index 3e1c80c..d0b6d23 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -158,6 +158,8 @@ macro_rules! int_trait_impl {
     )*)
 }
 int_trait_impl!(Num for usize u8 u16 u32 u64 isize i8 i16 i32 i64);
+#[cfg(feature = "i128")]
+int_trait_impl!(Num for u128 i128);
 
 impl<T: Num> Num for Wrapping<T>
     where Wrapping<T>: