diff --git a/backend-spring/src/main/java/com/erp/controller/DepartmentController.java b/backend-spring/src/main/java/com/erp/controller/DepartmentController.java
index 7ee10c98..48d90235 100644
--- a/backend-spring/src/main/java/com/erp/controller/DepartmentController.java
+++ b/backend-spring/src/main/java/com/erp/controller/DepartmentController.java
@@ -21,20 +21,22 @@ public class DepartmentController {
     /**
      * 부서 목록 조회 (회사별).
      * 기본은 active 부서만. ?include_deleted=true 시 soft-delete 된 부서도 포함.
-     * GET /api/departments/companies/{companyCode}/departments[?include_deleted=true]
+     * ?base_date=YYYY-MM-DD 시 해당 시점에 active 했던 부서만 반환.
+     * GET /api/departments/companies/{companyCode}/departments[?include_deleted=true][&base_date=YYYY-MM-DD]
      */
     @GetMapping("/companies/{companyCode}/departments")
     public ResponseEntity<ApiResponse<List<Map<String, Object>>>> getDepartments(
             @PathVariable String companyCode,
             @RequestAttribute("company_code") String userCompanyCode,
-            @RequestParam(value = "include_deleted", required = false, defaultValue = "false") boolean includeDeleted) {
+            @RequestParam(value = "include_deleted", required = false, defaultValue = "false") boolean includeDeleted,
+            @RequestParam(value = "base_date", required = false) String baseDate) {
 
         if (!isSuperAdmin(userCompanyCode) && !userCompanyCode.equals(companyCode)) {
             return ResponseEntity.status(403)
                     .body(ApiResponse.error("해당 회사의 부서를 조회할 권한이 없습니다."));
         }
 
-        List<Map<String, Object>> departments = departmentService.getDepartments(companyCode, includeDeleted);
+        List<Map<String, Object>> departments = departmentService.getDepartments(companyCode, includeDeleted, baseDate);
         return ResponseEntity.ok(ApiResponse.success(departments, "부서 목록 조회 성공"));
     }
 
diff --git a/backend-spring/src/main/java/com/erp/service/DepartmentService.java b/backend-spring/src/main/java/com/erp/service/DepartmentService.java
index e774d84c..57e993f8 100644
--- a/backend-spring/src/main/java/com/erp/service/DepartmentService.java
+++ b/backend-spring/src/main/java/com/erp/service/DepartmentService.java
@@ -20,17 +20,22 @@ public class DepartmentService extends BaseService {
     // ──────────────────────────────────────────────────
 
     public List<Map<String, Object>> getDepartments(String companyCode) {
-        return getDepartments(companyCode, false);
+        return getDepartments(companyCode, false, null);
     }
 
     /** soft-delete 대응 — includeDeleted=true 면 DELETED_AT 부서도 포함 */
     public List<Map<String, Object>> getDepartments(String companyCode, boolean includeDeleted) {
+        return getDepartments(companyCode, includeDeleted, null);
+    }
+
+    /** 기준일 필터 — baseDate 가 있으면 해당 시점에 active 한 부서만 반환 (start_date ≤ baseDate ≤ end_date OR end_date IS NULL) */
+    public List<Map<String, Object>> getDepartments(String companyCode, boolean includeDeleted, String baseDate) {
         Map<String, Object> params = new HashMap<>();
         params.put("company_code", companyCode);
         params.put("include_deleted", includeDeleted);
+        params.put("base_date", baseDate);  // null/빈문자면 XML if 가 skip
         List<Map<String, Object>> departments = sqlSession.selectList("department.selectDepartments", params);
 
-        // member_count를 int로 변환
         for (Map<String, Object> dept : departments) {
             Object cnt = dept.get("member_count");
             if (cnt != null) {
diff --git a/backend-spring/src/main/resources/mapper/department.xml b/backend-spring/src/main/resources/mapper/department.xml
index be469617..1c492644 100644
--- a/backend-spring/src/main/resources/mapper/department.xml
+++ b/backend-spring/src/main/resources/mapper/department.xml
@@ -30,6 +30,10 @@
     <if test="include_deleted == null or include_deleted == false">
       AND D.DELETED_AT IS NULL
     </if>
+    <if test="base_date != null and base_date != ''">
+      AND D.START_DATE &lt;= #{base_date}::date
+      AND (D.END_DATE IS NULL OR D.END_DATE &gt;= #{base_date}::date)
+    </if>
     GROUP BY
       D.DEPT_CODE, D.DEPT_NAME, D.COMPANY_CODE, D.PARENT_DEPT_CODE,
       D.SHORT_NAME, D.DEPT_TYPE, D.ORG_SYSTEM, D.APPROVAL_MANAGER, D.DEPT_MANAGER,
diff --git a/frontend/app/(main)/admin/userMng/deptMngList/page.tsx b/frontend/app/(main)/admin/userMng/deptMngList/page.tsx
index 5df0b9b2..df7da3f3 100644
--- a/frontend/app/(main)/admin/userMng/deptMngList/page.tsx
+++ b/frontend/app/(main)/admin/userMng/deptMngList/page.tsx
@@ -201,7 +201,10 @@ export default function DeptMngListPage() {
     if (!selectedCompanyCode) return;
     setIsTreeLoading(true);
     try {
-      const res = await departmentAPI.getDepartments(selectedCompanyCode, { includeDeleted: showDeleted });
+      const res = await departmentAPI.getDepartments(selectedCompanyCode, {
+        includeDeleted: showDeleted,
+        baseDate: periodMode === "date" ? baseDate : undefined,
+      });
       if (res.success && (res as any).data) {
         setDepartments((res as any).data);
       } else {
@@ -210,7 +213,7 @@ export default function DeptMngListPage() {
     } finally {
       setIsTreeLoading(false);
     }
-  }, [selectedCompanyCode, showDeleted]);
+  }, [selectedCompanyCode, showDeleted, periodMode, baseDate]);
 
   useEffect(() => {
     loadDepartments();
@@ -645,33 +648,30 @@ export default function DeptMngListPage() {
         <aside className="flex w-[340px] shrink-0 flex-col border-r">
           {/* 기준일 / 회사 / 검색 */}
           <div className="space-y-3 border-b p-3">
-            {/* TODO V2: 사용기간 필터 — backend 미구현, V1 hidden */}
-            {false && (
-              <div className="flex items-center gap-3">
-                <Label className="w-[60px] shrink-0 text-xs font-semibold">사용기간</Label>
-                <RadioGroup
-                  value={periodMode}
-                  onValueChange={(v) => setPeriodMode(v as "all" | "date")}
-                  className="flex items-center gap-3"
-                >
-                  <div className="flex items-center gap-1">
-                    <RadioGroupItem value="all" id="period-all" className="h-3.5 w-3.5" />
-                    <Label htmlFor="period-all" className="text-xs">전체</Label>
-                  </div>
-                  <div className="flex items-center gap-1">
-                    <RadioGroupItem value="date" id="period-date" className="h-3.5 w-3.5" />
-                    <Label htmlFor="period-date" className="text-xs">기준일</Label>
-                  </div>
-                </RadioGroup>
-                <Input
-                  type="date"
-                  value={baseDate}
-                  onChange={(e) => setBaseDate(e.target.value)}
-                  disabled={periodMode !== "date"}
-                  className="h-7 flex-1 text-xs"
-                />
-              </div>
-            )}
+            <div className="flex items-center gap-3">
+              <Label className="w-[60px] shrink-0 text-xs font-semibold">사용기간</Label>
+              <RadioGroup
+                value={periodMode}
+                onValueChange={(v) => setPeriodMode(v as "all" | "date")}
+                className="flex items-center gap-3"
+              >
+                <div className="flex items-center gap-1">
+                  <RadioGroupItem value="all" id="period-all" className="h-3.5 w-3.5" />
+                  <Label htmlFor="period-all" className="text-xs">전체</Label>
+                </div>
+                <div className="flex items-center gap-1">
+                  <RadioGroupItem value="date" id="period-date" className="h-3.5 w-3.5" />
+                  <Label htmlFor="period-date" className="text-xs">기준일</Label>
+                </div>
+              </RadioGroup>
+              <Input
+                type="date"
+                value={baseDate}
+                onChange={(e) => setBaseDate(e.target.value)}
+                disabled={periodMode !== "date"}
+                className="h-7 flex-1 text-xs"
+              />
+            </div>
 
             <Select
               value={selectedCompanyCode}
@@ -1423,28 +1423,25 @@ function BasicInfoForm({
           </RadioGroup>
         </Row>
 
-        {/* TODO V2: 사용기간 (시작일/종료일) — 필터 도입 시 사용. 컬럼은 DEPT_INFO.START_DATE/END_DATE 유지 */}
-        {false && (
-          <Row label="시작일">
-            <div className="grid grid-cols-2 gap-3">
+        <Row label="시작일">
+          <div className="grid grid-cols-2 gap-3">
+            <Input
+              type="date"
+              value={draft.start_date}
+              onChange={(e) => update("start_date", e.target.value)}
+              className="h-8 text-sm"
+            />
+            <div className="flex items-center gap-2">
+              <Label className="w-[50px] text-xs">종료일</Label>
               <Input
                 type="date"
-                value={draft.start_date}
-                onChange={(e) => update("start_date", e.target.value)}
-                className="h-8 text-sm"
+                value={draft.end_date}
+                onChange={(e) => update("end_date", e.target.value)}
+                className="h-8 flex-1 text-sm"
               />
-              <div className="flex items-center gap-2">
-                <Label className="w-[50px] text-xs">종료일</Label>
-                <Input
-                  type="date"
-                  value={draft.end_date}
-                  onChange={(e) => update("end_date", e.target.value)}
-                  className="h-8 flex-1 text-sm"
-                />
-              </div>
             </div>
-          </Row>
-        )}
+          </div>
+        </Row>
 
         <Row label="정렬">
           <Input
diff --git a/frontend/lib/api/department.ts b/frontend/lib/api/department.ts
index 34be751a..41a1f6f3 100644
--- a/frontend/lib/api/department.ts
+++ b/frontend/lib/api/department.ts
@@ -8,15 +8,19 @@ import { Department, DepartmentMember, DepartmentFormData } from "@/types/depart
 /**
  * 부서 목록 조회 (회사별).
  * options.includeDeleted=true 시 soft-delete 된 부서도 포함.
+ * options.baseDate (YYYY-MM-DD) 가 있으면 해당 시점에 active 한 부서만 반환.
  */
 export async function getDepartments(
   companyCode: string,
-  options?: { includeDeleted?: boolean },
+  options?: { includeDeleted?: boolean; baseDate?: string },
 ) {
   try {
     const url = `/departments/companies/${companyCode}/departments`;
+    const params: Record<string, any> = {};
+    if (options?.includeDeleted) params.include_deleted = true;
+    if (options?.baseDate) params.base_date = options.baseDate;
     const response = await apiClient.get<{ success: boolean; data: Department[] }>(url, {
-      params: options?.includeDeleted ? { include_deleted: true } : undefined,
+      params: Object.keys(params).length > 0 ? params : undefined,
     });
     return response.data;
   } catch (error: any) {