diff --git a/experimental/CHANGELOG.md b/experimental/CHANGELOG.md
index 23bce4b247..86f868f6f5 100644
--- a/experimental/CHANGELOG.md
+++ b/experimental/CHANGELOG.md
@@ -35,6 +35,7 @@ All notable changes to experimental packages in this project will be documented
 * feat(exporter-logs-otlp-grpc): otlp-grpc exporter for logs. [#3712](https://github.com/open-telemetry/opentelemetry-js/pull/3712/) @llc1123
 * feat(otlp-grpc-exporter-base): use statically generated protobuf code [#3705](https://github.com/open-telemetry/opentelemetry-js/pull/3705) @pichlermarc
 * refactor(otlp-transformer): refine metric transformers. [#3770](https://github.com/open-telemetry/opentelemetry-js/pull/3770/) @llc1123
+* feat(api-logs): add `ObservedTimestamp` to `LogRecord`. [#3787](https://github.com/open-telemetry/opentelemetry-js/pull/3787/) @llc1123
 
 ### :bug: (Bug Fix)
 
diff --git a/experimental/packages/api-logs/src/types/LogRecord.ts b/experimental/packages/api-logs/src/types/LogRecord.ts
index a2c7d25ad3..e1c1100c5f 100644
--- a/experimental/packages/api-logs/src/types/LogRecord.ts
+++ b/experimental/packages/api-logs/src/types/LogRecord.ts
@@ -50,6 +50,11 @@ export interface LogRecord {
    */
   timestamp?: number;
 
+  /**
+   * Time when the event was observed by the collection system.
+   */
+  observedTimestamp?: number;
+
   /**
    * Numerical value of the severity.
    */
diff --git a/experimental/packages/exporter-logs-otlp-grpc/test/logsHelper.ts b/experimental/packages/exporter-logs-otlp-grpc/test/logsHelper.ts
index b57b2682bd..1dfd82675a 100644
--- a/experimental/packages/exporter-logs-otlp-grpc/test/logsHelper.ts
+++ b/experimental/packages/exporter-logs-otlp-grpc/test/logsHelper.ts
@@ -45,6 +45,7 @@ export const mockedReadableLogRecord: ReadableLogRecord = {
     schemaUrl: 'http://url.to.schema',
   },
   hrTime: [1680253513, 123241635] as HrTime,
+  hrTimeObserved: [1683526948, 965142784] as HrTime,
   attributes: {
     'some-attribute': 'some attribute value',
   },
@@ -92,7 +93,7 @@ export function ensureExportedLogRecordIsCorrect(logRecord: ILogRecord) {
   );
   assert.strictEqual(
     logRecord.observedTimeUnixNano,
-    '1680253513123241728',
+    '1683526948965142784',
     'observedTimeUnixNano is wrong'
   );
   assert.strictEqual(
diff --git a/experimental/packages/otlp-transformer/src/logs/index.ts b/experimental/packages/otlp-transformer/src/logs/index.ts
index 4fd114fa69..6fa4d11e86 100644
--- a/experimental/packages/otlp-transformer/src/logs/index.ts
+++ b/experimental/packages/otlp-transformer/src/logs/index.ts
@@ -93,7 +93,7 @@ function logRecordsToResourceLogs(
 function toLogRecord(log: ReadableLogRecord, useHex?: boolean): ILogRecord {
   return {
     timeUnixNano: hrTimeToNanoseconds(log.hrTime),
-    observedTimeUnixNano: hrTimeToNanoseconds(log.hrTime),
+    observedTimeUnixNano: hrTimeToNanoseconds(log.hrTimeObserved),
     severityNumber: toSeverityNumber(log.severityNumber),
     severityText: log.severityText,
     body: toAnyValue(log.body),
diff --git a/experimental/packages/otlp-transformer/test/logs.test.ts b/experimental/packages/otlp-transformer/test/logs.test.ts
index c184134ce4..ef0a4cf9d7 100644
--- a/experimental/packages/otlp-transformer/test/logs.test.ts
+++ b/experimental/packages/otlp-transformer/test/logs.test.ts
@@ -52,7 +52,7 @@ function createExpectedLogJson(useHex: boolean): IExportLogsServiceRequest {
                 // eslint-disable-next-line @typescript-eslint/no-loss-of-precision
                 timeUnixNano: 1680253513123241635,
                 // eslint-disable-next-line @typescript-eslint/no-loss-of-precision
-                observedTimeUnixNano: 1680253513123241635,
+                observedTimeUnixNano: 1683526948965142784,
                 severityNumber: ESeverityNumber.SEVERITY_NUMBER_ERROR,
                 severityText: 'error',
                 body: { stringValue: 'some_log_body' },
@@ -105,6 +105,7 @@ describe('Logs', () => {
       };
       const log_fragment_1 = {
         hrTime: [1680253513, 123241635] as HrTime,
+        hrTimeObserved: [1683526948, 965142784] as HrTime,
         attributes: {
           'some-attribute': 'some attribute value',
         },
@@ -119,6 +120,7 @@ describe('Logs', () => {
       };
       const log_fragment_2 = {
         hrTime: [1680253797, 687038506] as HrTime,
+        hrTimeObserved: [1680253797, 687038506] as HrTime,
         attributes: {
           'another-attribute': 'another attribute value',
         },
diff --git a/experimental/packages/sdk-logs/src/LogRecord.ts b/experimental/packages/sdk-logs/src/LogRecord.ts
index a4601af6fc..9d3e909feb 100644
--- a/experimental/packages/sdk-logs/src/LogRecord.ts
+++ b/experimental/packages/sdk-logs/src/LogRecord.ts
@@ -30,6 +30,7 @@ import { Logger } from './Logger';
 
 export class LogRecord implements ReadableLogRecord {
   readonly hrTime: api.HrTime;
+  readonly hrTimeObserved: api.HrTime;
   readonly spanContext?: api.SpanContext;
   readonly resource: IResource;
   readonly instrumentationScope: InstrumentationScope;
@@ -73,7 +74,8 @@ export class LogRecord implements ReadableLogRecord {
 
   constructor(logger: Logger, logRecord: logsAPI.LogRecord) {
     const {
-      timestamp = Date.now(),
+      timestamp,
+      observedTimestamp,
       severityNumber,
       severityText,
       body,
@@ -81,7 +83,10 @@ export class LogRecord implements ReadableLogRecord {
       context,
     } = logRecord;
 
-    this.hrTime = timeInputToHrTime(timestamp);
+    const now = Date.now();
+    this.hrTime = timeInputToHrTime(timestamp ?? now);
+    this.hrTimeObserved = timeInputToHrTime(observedTimestamp ?? now);
+
     if (context) {
       const spanContext = api.trace.getSpanContext(context);
       if (spanContext && api.isSpanContextValid(spanContext)) {
diff --git a/experimental/packages/sdk-logs/src/export/ReadableLogRecord.ts b/experimental/packages/sdk-logs/src/export/ReadableLogRecord.ts
index e02d53dae9..72fe7d1d35 100644
--- a/experimental/packages/sdk-logs/src/export/ReadableLogRecord.ts
+++ b/experimental/packages/sdk-logs/src/export/ReadableLogRecord.ts
@@ -21,6 +21,7 @@ import type { SeverityNumber } from '@opentelemetry/api-logs';
 
 export interface ReadableLogRecord {
   readonly hrTime: HrTime;
+  readonly hrTimeObserved: HrTime;
   readonly spanContext?: SpanContext;
   readonly severityText?: string;
   readonly severityNumber?: SeverityNumber;