diff --git a/src/serde/deserialize.rs b/src/serde/deserialize.rs
index d8593c5c..c8f59bd8 100644
--- a/src/serde/deserialize.rs
+++ b/src/serde/deserialize.rs
@@ -94,7 +94,7 @@ impl<'de> Visitor<'de> for DynamicVisitor {
         return Ok(Dynamic::from(v as INT));
 
         #[cfg(feature = "only_i32")]
-        if v <= INT::MAX as i32 {
+        if v <= INT::MAX as u32 {
             return Ok(Dynamic::from(v as INT));
         }
 
diff --git a/src/serde/ser.rs b/src/serde/ser.rs
index a2020714..c4030dbd 100644
--- a/src/serde/ser.rs
+++ b/src/serde/ser.rs
@@ -189,7 +189,7 @@ impl Serializer for &mut DynamicSerializer {
         return Ok(Dynamic::from(v as INT));
 
         #[cfg(feature = "only_i32")]
-        if v <= INT::MAX as i32 {
+        if v <= INT::MAX as u32 {
             return Ok(Dynamic::from(v as INT));
         }