diff --git a/src/components/production/WorkerScreen/actions.ts b/src/components/production/WorkerScreen/actions.ts
index 6dc3ab90..04726d6e 100644
--- a/src/components/production/WorkerScreen/actions.ts
+++ b/src/components/production/WorkerScreen/actions.ts
@@ -243,7 +243,8 @@ export async function completeWorkOrder(
     errorMessage: '작업 완료 처리에 실패했습니다.',
   });
   if (!result.success) return { success: false, error: result.error };
-  const lotNo = `KD-SA-${new Date().toISOString().slice(2, 10).replace(/-/g, '')}-01`;
+  // 백엔드에서 생성한 실제 LOT 번호 사용
+  const lotNo = result.data?.lot_no || null;
   return { success: true, lotNo };
 }
 
diff --git a/src/components/production/WorkerScreen/index.tsx b/src/components/production/WorkerScreen/index.tsx
index 66dfbde7..f09ae389 100644
--- a/src/components/production/WorkerScreen/index.tsx
+++ b/src/components/production/WorkerScreen/index.tsx
@@ -1016,18 +1016,10 @@ export default function WorkerScreen() {
     setIsMaterialModalOpen(true);
   }, []);
 
-  // MaterialInputModal 완료 후 → 작업 완료 결과 팝업
-  const handleWorkCompletion = useCallback(() => {
+  // MaterialInputModal 완료 후 → API 완료 처리 → 결과 팝업
+  const handleWorkCompletion = useCallback(async () => {
     if (!selectedOrder) return;
-    const lotNo = `KD-SA-${new Date().toISOString().slice(2, 10).replace(/-/g, '')}-01`;
-    setCompletionLotNo(lotNo);
-    setIsCompletionResultOpen(true);
     setIsCompletionFlow(false);
-  }, [selectedOrder]);
-
-  // 완료 결과 팝업 확인 → API 완료 처리
-  const handleCompletionResultConfirm = useCallback(async () => {
-    if (!selectedOrder) return;
 
     try {
       const materials = inputMaterialsMap.get(selectedOrder.id);
@@ -1041,7 +1033,9 @@ export default function WorkerScreen() {
       );
 
       if (result.success) {
-        toast.success('작업이 완료되었습니다.');
+        // 백엔드에서 받은 실제 LOT 번호로 결과 팝업 표시
+        setCompletionLotNo(result.lotNo || '');
+        setIsCompletionResultOpen(true);
         setInputMaterialsMap((prev) => {
           const next = new Map(prev);
           next.delete(selectedOrder.id);
@@ -1053,14 +1047,17 @@ export default function WorkerScreen() {
       }
     } catch (error) {
       if (isNextRedirectError(error)) throw error;
-      console.error('[WorkerScreen] handleCompletionResultConfirm error:', error);
+      console.error('[WorkerScreen] handleWorkCompletion error:', error);
       toast.error('작업 완료 중 오류가 발생했습니다.');
-    } finally {
-      setSelectedOrder(null);
-      setCompletionLotNo('');
     }
   }, [selectedOrder, inputMaterialsMap]);
 
+  // 완료 결과 팝업 확인 → 상태 정리
+  const handleCompletionResultConfirm = useCallback(() => {
+    setSelectedOrder(null);
+    setCompletionLotNo('');
+  }, []);
+
   // 하단 버튼용 합성 WorkOrder (사이드바 선택 우선, 없으면 첫 번째, 그래도 없으면 목업 폴백)
   const getTargetOrder = useCallback((): WorkOrder | null => {
     // 사이드바에서 선택된 작업지시 우선