diff --git a/CHANGELOG.md b/CHANGELOG.md
index b7b8a06ef3..c5f1569a88 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 ### :bug: (Bug Fix)
 
 * fix(opentelemetry-exporter-logs-otlp-http): Add otel-api as dev dep for tests as they are directly importing the api and which is breaking the web-sandbox tests which is using rollup
+* fix(core): stop rounding to nearest int in hrTimeTo*seconds() functions [#4014](https://github.com/open-telemetry/opentelemetry-js/pull/4014/) @aabmass
 
 ### :books: (Refine Doc)
 
diff --git a/packages/opentelemetry-core/src/common/time.ts b/packages/opentelemetry-core/src/common/time.ts
index 8dd650a992..8d3051b00c 100644
--- a/packages/opentelemetry-core/src/common/time.ts
+++ b/packages/opentelemetry-core/src/common/time.ts
@@ -129,7 +129,7 @@ export function hrTimeToNanoseconds(time: api.HrTime): number {
  * @param time
  */
 export function hrTimeToMilliseconds(time: api.HrTime): number {
-  return Math.round(time[0] * 1e3 + time[1] / 1e6);
+  return time[0] * 1e3 + time[1] / 1e6;
 }
 
 /**
@@ -137,7 +137,7 @@ export function hrTimeToMilliseconds(time: api.HrTime): number {
  * @param time
  */
 export function hrTimeToMicroseconds(time: api.HrTime): number {
-  return Math.round(time[0] * 1e6 + time[1] / 1e3);
+  return time[0] * 1e6 + time[1] / 1e3;
 }
 
 /**
diff --git a/packages/opentelemetry-shim-opentracing/test/Shim.test.ts b/packages/opentelemetry-shim-opentracing/test/Shim.test.ts
index cd3749a681..2da2f80003 100644
--- a/packages/opentelemetry-shim-opentracing/test/Shim.test.ts
+++ b/packages/opentelemetry-shim-opentracing/test/Shim.test.ts
@@ -261,7 +261,7 @@ describe('OpenTracing Shim', () => {
         assert.strictEqual(otSpan.links.length, 1);
         assert.deepStrictEqual(
           hrTimeToMilliseconds(otSpan.startTime),
-          Math.round(now + adjustment + performance.timeOrigin)
+          now + adjustment + performance.timeOrigin
         );
         assert.deepStrictEqual(otSpan.attributes, opentracingOptions.tags);
       });
@@ -495,7 +495,7 @@ describe('OpenTracing Shim', () => {
       const adjustment = otSpan['_performanceOffset'];
       assert.deepStrictEqual(
         hrTimeToMilliseconds(otSpan.endTime),
-        Math.round(now + adjustment + performance.timeOrigin)
+        now + adjustment + performance.timeOrigin
       );
     });