diff --git a/packages/durabletask-js/src/orchestration/enum/orchestration-status.enum.ts b/packages/durabletask-js/src/orchestration/enum/orchestration-status.enum.ts
index 64aff91..02f65b7 100644
--- a/packages/durabletask-js/src/orchestration/enum/orchestration-status.enum.ts
+++ b/packages/durabletask-js/src/orchestration/enum/orchestration-status.enum.ts
@@ -28,6 +28,7 @@ export enum OrchestrationStatus {
   RUNNING = pb.OrchestrationStatus.ORCHESTRATION_STATUS_RUNNING,
   COMPLETED = pb.OrchestrationStatus.ORCHESTRATION_STATUS_COMPLETED,
   FAILED = pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED,
+  CANCELED = pb.OrchestrationStatus.ORCHESTRATION_STATUS_CANCELED,
   TERMINATED = pb.OrchestrationStatus.ORCHESTRATION_STATUS_TERMINATED,
   CONTINUED_AS_NEW = pb.OrchestrationStatus.ORCHESTRATION_STATUS_CONTINUED_AS_NEW,
   PENDING = pb.OrchestrationStatus.ORCHESTRATION_STATUS_PENDING,
diff --git a/packages/durabletask-js/src/testing/in-memory-backend.ts b/packages/durabletask-js/src/testing/in-memory-backend.ts
index 1d55189..cf81627 100644
--- a/packages/durabletask-js/src/testing/in-memory-backend.ts
+++ b/packages/durabletask-js/src/testing/in-memory-backend.ts
@@ -490,6 +490,8 @@ export class InMemoryOrchestrationBackend {
         return ClientOrchestrationStatus.FAILED;
       case pb.OrchestrationStatus.ORCHESTRATION_STATUS_TERMINATED:
         return ClientOrchestrationStatus.TERMINATED;
+      case pb.OrchestrationStatus.ORCHESTRATION_STATUS_CANCELED:
+        return ClientOrchestrationStatus.CANCELED;
       case pb.OrchestrationStatus.ORCHESTRATION_STATUS_SUSPENDED:
         return ClientOrchestrationStatus.SUSPENDED;
       case pb.OrchestrationStatus.ORCHESTRATION_STATUS_CONTINUED_AS_NEW:
@@ -511,6 +513,7 @@ export class InMemoryOrchestrationBackend {
     return (
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_COMPLETED ||
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED ||
+      status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_CANCELED ||
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_TERMINATED
     );
   }
diff --git a/packages/durabletask-js/src/testing/test-client.ts b/packages/durabletask-js/src/testing/test-client.ts
index 09d1538..5c68335 100644
--- a/packages/durabletask-js/src/testing/test-client.ts
+++ b/packages/durabletask-js/src/testing/test-client.ts
@@ -151,6 +151,7 @@ export class TestOrchestrationClient {
     return (
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_COMPLETED ||
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED ||
+      status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_CANCELED ||
       status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_TERMINATED
     );
   }
diff --git a/packages/durabletask-js/test/in-memory-backend.spec.ts b/packages/durabletask-js/test/in-memory-backend.spec.ts
index 381fcde..86e4d10 100644
--- a/packages/durabletask-js/test/in-memory-backend.spec.ts
+++ b/packages/durabletask-js/test/in-memory-backend.spec.ts
@@ -602,6 +602,30 @@ describe("In-Memory Backend", () => {
     expect(state?.serializedOutput).toEqual(JSON.stringify(42));
   });
 
+  describe("toClientStatus", () => {
+    it("should map CANCELED proto status to CANCELED client status", () => {
+      const { OrchestrationStatus: pbStatus } = require("../src/proto/orchestrator_service_pb");
+      expect(backend.toClientStatus(pbStatus.ORCHESTRATION_STATUS_CANCELED)).toBe(OrchestrationStatus.CANCELED);
+    });
+
+    it("should map all known proto statuses without throwing", () => {
+      const { OrchestrationStatus: pbStatus } = require("../src/proto/orchestrator_service_pb");
+      const protoStatuses = [
+        pbStatus.ORCHESTRATION_STATUS_RUNNING,
+        pbStatus.ORCHESTRATION_STATUS_COMPLETED,
+        pbStatus.ORCHESTRATION_STATUS_CONTINUED_AS_NEW,
+        pbStatus.ORCHESTRATION_STATUS_FAILED,
+        pbStatus.ORCHESTRATION_STATUS_CANCELED,
+        pbStatus.ORCHESTRATION_STATUS_TERMINATED,
+        pbStatus.ORCHESTRATION_STATUS_PENDING,
+        pbStatus.ORCHESTRATION_STATUS_SUSPENDED,
+      ];
+      for (const status of protoStatuses) {
+        expect(() => backend.toClientStatus(status)).not.toThrow();
+      }
+    });
+  });
+
   it("waitForState with zero timeout should wait indefinitely until state matches", async () => {
     const orchestrator: TOrchestrator = async (_: OrchestrationContext) => "done";
 
diff --git a/packages/durabletask-js/test/orchestration-status.spec.ts b/packages/durabletask-js/test/orchestration-status.spec.ts
new file mode 100644
index 0000000..96368f1
--- /dev/null
+++ b/packages/durabletask-js/test/orchestration-status.spec.ts
@@ -0,0 +1,86 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+import * as pb from "../src/proto/orchestrator_service_pb";
+import { OrchestrationStatus, fromProtobuf, toProtobuf } from "../src/orchestration/enum/orchestration-status.enum";
+
+/**
+ * Exhaustive mapping between client OrchestrationStatus and proto OrchestrationStatus.
+ * Every entry in the proto enum (except unspecified/unknown sentinel values) must have
+ * a corresponding client enum member.
+ */
+const STATUS_PAIRS: [OrchestrationStatus, pb.OrchestrationStatus][] = [
+  [OrchestrationStatus.RUNNING, pb.OrchestrationStatus.ORCHESTRATION_STATUS_RUNNING],
+  [OrchestrationStatus.COMPLETED, pb.OrchestrationStatus.ORCHESTRATION_STATUS_COMPLETED],
+  [OrchestrationStatus.CONTINUED_AS_NEW, pb.OrchestrationStatus.ORCHESTRATION_STATUS_CONTINUED_AS_NEW],
+  [OrchestrationStatus.FAILED, pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED],
+  [OrchestrationStatus.CANCELED, pb.OrchestrationStatus.ORCHESTRATION_STATUS_CANCELED],
+  [OrchestrationStatus.TERMINATED, pb.OrchestrationStatus.ORCHESTRATION_STATUS_TERMINATED],
+  [OrchestrationStatus.PENDING, pb.OrchestrationStatus.ORCHESTRATION_STATUS_PENDING],
+  [OrchestrationStatus.SUSPENDED, pb.OrchestrationStatus.ORCHESTRATION_STATUS_SUSPENDED],
+];
+
+describe("OrchestrationStatus enum", () => {
+  describe("fromProtobuf", () => {
+    it.each(STATUS_PAIRS)(
+      "should convert client %s from proto %s",
+      (clientStatus, protoStatus) => {
+        expect(fromProtobuf(protoStatus)).toBe(clientStatus);
+      },
+    );
+
+    it("should throw on unknown proto value", () => {
+      expect(() => fromProtobuf(999 as pb.OrchestrationStatus)).toThrow(
+        "Unknown protobuf OrchestrationStatus value: 999",
+      );
+    });
+  });
+
+  describe("toProtobuf", () => {
+    it.each(STATUS_PAIRS)(
+      "should convert client %s to proto %s",
+      (clientStatus, protoStatus) => {
+        expect(toProtobuf(clientStatus)).toBe(protoStatus);
+      },
+    );
+
+    it("should throw on unknown client value", () => {
+      expect(() => toProtobuf(999 as OrchestrationStatus)).toThrow(
+        "Unknown OrchestrationStatus value: 999",
+      );
+    });
+  });
+
+  describe("round-trip", () => {
+    it.each(STATUS_PAIRS)(
+      "should round-trip client %s through proto and back",
+      (clientStatus) => {
+        expect(fromProtobuf(toProtobuf(clientStatus))).toBe(clientStatus);
+      },
+    );
+  });
+
+  describe("completeness", () => {
+    it("should cover all non-zero proto OrchestrationStatus values", () => {
+      // Get all numeric values from the proto enum (protobuf JS enums are plain objects)
+      const protoValues = new Set<number>();
+      for (const [key, value] of Object.entries(pb.OrchestrationStatus)) {
+        if (typeof value === "number" && key.startsWith("ORCHESTRATION_STATUS_")) {
+          protoValues.add(value);
+        }
+      }
+
+      const coveredProtoValues = new Set(STATUS_PAIRS.map(([, proto]) => proto as number));
+
+      for (const protoValue of protoValues) {
+        expect(coveredProtoValues).toContain(protoValue);
+      }
+    });
+
+    it("should have matching numeric values between client and proto enums", () => {
+      for (const [clientStatus, protoStatus] of STATUS_PAIRS) {
+        expect(clientStatus as number).toBe(protoStatus as number);
+      }
+    });
+  });
+});