diff --git a/experimental/CHANGELOG.md b/experimental/CHANGELOG.md
index e69d5617b87..978ca31b371 100644
--- a/experimental/CHANGELOG.md
+++ b/experimental/CHANGELOG.md
@@ -13,6 +13,7 @@ For notes on migrating to 2.x / 0.200.x see [the upgrade guide](doc/upgrade-to-2
 ### :bug: Bug Fixes
 
 * fix(instrumentation-http): respect requireParent flag when INVALID_SPAN_CONTEXT is used [#4788](https://github.com/open-telemetry/opentelemetry-js/pull/4788) @reberhardt7
+* fix(otlp-transformer): trunc hrTime to int for nanos converting [#5924](https://github.com/open-telemetry/opentelemetry-js/pull/5924) @blumamir
 
 ### :books: Documentation
 
diff --git a/experimental/packages/otlp-transformer/src/common/utils.ts b/experimental/packages/otlp-transformer/src/common/utils.ts
index 756e80f4a4d..f4f8cb65e41 100644
--- a/experimental/packages/otlp-transformer/src/common/utils.ts
+++ b/experimental/packages/otlp-transformer/src/common/utils.ts
@@ -21,7 +21,9 @@ import { hexToBinary } from './hex-to-binary';
 
 export function hrTimeToNanos(hrTime: HrTime): bigint {
   const NANOSECONDS = BigInt(1_000_000_000);
-  return BigInt(hrTime[0]) * NANOSECONDS + BigInt(hrTime[1]);
+  return (
+    BigInt(Math.trunc(hrTime[0])) * NANOSECONDS + BigInt(Math.trunc(hrTime[1]))
+  );
 }
 
 export function toLongBits(value: bigint): LongBits {
diff --git a/experimental/packages/otlp-transformer/test/trace.test.ts b/experimental/packages/otlp-transformer/test/trace.test.ts
index f76ea753f24..9fad977170f 100644
--- a/experimental/packages/otlp-transformer/test/trace.test.ts
+++ b/experimental/packages/otlp-transformer/test/trace.test.ts
@@ -544,6 +544,12 @@ describe('Trace', () => {
       assert.deepStrictEqual(JSON.parse(decoder.decode(serialized)), expected);
     });
 
+    it('hrtime contains float value', () => {
+      const span = createSpanWithResource(resource);
+      (span as any).startTime = [1640715557.5, 342725388.5];
+      JsonTraceSerializer.serializeRequest([span]);
+    });
+
     it('deserializes a response', () => {
       const expectedResponse = {
         partialSuccess: {