diff --git a/code-generator/src/main/java/io/streamnative/lightproto/generator/LightProtoNumberField.java b/code-generator/src/main/java/io/streamnative/lightproto/generator/LightProtoNumberField.java
index c297299..31ad40c 100644
--- a/code-generator/src/main/java/io/streamnative/lightproto/generator/LightProtoNumberField.java
+++ b/code-generator/src/main/java/io/streamnative/lightproto/generator/LightProtoNumberField.java
@@ -55,8 +55,10 @@ static void serializeNumber(PrintWriter w, ProtoFieldDescriptor field, String na
         } else if (field.getProtoType().equals("bool")) {
             writer = "writeRawByte";
             value = name + " ? 1 : 0";
-        } else if (field.getProtoType().equals("int32") || field.getProtoType().equals("uint32")) {
+        } else if (field.getProtoType().equals("int32")) {
             writer = "writeRawVarInt";
+        } else if (field.getProtoType().equals("uint32")) {
+            writer = "writeRawVarUInt";
         } else if (field.getProtoType().equals("sint32")) {
             writer = "writeRawSignedVarInt";
         } else if (field.getProtoType().equals("sint64")) {
@@ -140,7 +142,7 @@ static String serializedSizeOfNumber(ProtoFieldDescriptor field, String name) {
         } else if (field.getProtoType().equals("int32")) {
             return String.format("LightProtoCodec.computeVarIntSize(%s)", name);
         } else if (field.getProtoType().equals("uint32")) {
-            return String.format("LightProtoCodec.computeVarIntSize(%s)", name);
+            return String.format("LightProtoCodec.computeVarUIntSize(%s)", name);
         } else if (field.getProtoType().equals("int64")) {
             return String.format("LightProtoCodec.computeVarInt64Size(%s)", name);
         } else if (field.getProtoType().equals("uint64")) {
diff --git a/code-generator/src/main/resources/io/streamnative/lightproto/generator/LightProtoCodec.java b/code-generator/src/main/resources/io/streamnative/lightproto/generator/LightProtoCodec.java
index 619030a..c4ddb0e 100644
--- a/code-generator/src/main/resources/io/streamnative/lightproto/generator/LightProtoCodec.java
+++ b/code-generator/src/main/resources/io/streamnative/lightproto/generator/LightProtoCodec.java
@@ -427,7 +427,7 @@ static int writeRawVarInt64(byte[] a, int i, long value) {
 
     /**
      * Writes n as an unsigned 32-bit varint, at most 5 bytes, as protobuf encodes
-     * zigzag-encoded sint32 values: what computeVarUIntSize() counts.
+     * uint32 and zigzag-encoded sint32 values: what computeVarUIntSize() counts.
      * writeRawVarInt() is the int32 encoding, which writes a negative n as 10 bytes.
      */
     static int writeRawVarUInt(byte[] a, int i, int n) {
diff --git a/tests/src/test/java/io/streamnative/lightproto/tests/NumbersTest.java b/tests/src/test/java/io/streamnative/lightproto/tests/NumbersTest.java
index e130f4d..c2f6522 100644
--- a/tests/src/test/java/io/streamnative/lightproto/tests/NumbersTest.java
+++ b/tests/src/test/java/io/streamnative/lightproto/tests/NumbersTest.java
@@ -206,6 +206,13 @@ public void testNumberFields() throws Exception {
         verify(lpn, pbn.build());
     }
 
+    @ParameterizedTest
+    @ValueSource(ints = {Integer.MIN_VALUE, -1})
+    public void testUint32AboveIntMax(int value) throws Exception {
+        // 2^31 and 2^32 - 1: protobuf writes a uint32 as an unsigned varint, 5 bytes
+        verify(new Numbers().setXUint32(value), NumbersOuterClass.Numbers.newBuilder().setXUint32(value).build());
+    }
+
     @ParameterizedTest
     @ValueSource(ints = {1 << 30, -(1 << 30) - 1, Integer.MAX_VALUE, Integer.MIN_VALUE})
     public void testSint32WithZigZagTopBitSet(int value) throws Exception {
diff --git a/tests/src/test/java/io/streamnative/lightproto/tests/RepeatedNumbersTest.java b/tests/src/test/java/io/streamnative/lightproto/tests/RepeatedNumbersTest.java
index 08d8ff0..1495be6 100644
--- a/tests/src/test/java/io/streamnative/lightproto/tests/RepeatedNumbersTest.java
+++ b/tests/src/test/java/io/streamnative/lightproto/tests/RepeatedNumbersTest.java
@@ -503,4 +503,22 @@ public void testSint32WithZigZagTopBitSet() throws Exception {
         assertArrayEquals(pb.build().toByteArray(), lp.toByteArray());
         assertArrayEquals(pbPacked.build().toByteArray(), lpPacked.toByteArray());
     }
+
+    @Test
+    public void testUint32AboveIntMax() throws Exception {
+        // 2^31 and 2^32 - 1: protobuf writes a uint32 as an unsigned varint, 5 bytes
+        int[] values = {Integer.MIN_VALUE, -1};
+        Repeated lp = new Repeated();
+        RepeatedPacked lpPacked = new RepeatedPacked();
+        RepeatedNumbers.Repeated.Builder pb = RepeatedNumbers.Repeated.newBuilder();
+        RepeatedNumbers.RepeatedPacked.Builder pbPacked = RepeatedNumbers.RepeatedPacked.newBuilder();
+        for (int value : values) {
+            lp.addXUint32(value);
+            lpPacked.addXUint32(value);
+            pb.addXUint32(value);
+            pbPacked.addXUint32(value);
+        }
+        assertArrayEquals(pb.build().toByteArray(), lp.toByteArray());
+        assertArrayEquals(pbPacked.build().toByteArray(), lpPacked.toByteArray());
+    }
 }