diff --git a/backend/src/main/java/de/effigenix/application/inventory/DeactivateStorageLocation.java b/backend/src/main/java/de/effigenix/application/inventory/DeactivateStorageLocation.java
index a11e1bb..083abfb 100644
--- a/backend/src/main/java/de/effigenix/application/inventory/DeactivateStorageLocation.java
+++ b/backend/src/main/java/de/effigenix/application/inventory/DeactivateStorageLocation.java
@@ -9,9 +9,11 @@ import org.springframework.transaction.annotation.Transactional;
 public class DeactivateStorageLocation {
 
     private final StorageLocationRepository storageLocationRepository;
+    private final StockRepository stockRepository;
 
-    public DeactivateStorageLocation(StorageLocationRepository storageLocationRepository) {
+    public DeactivateStorageLocation(StorageLocationRepository storageLocationRepository, StockRepository stockRepository) {
         this.storageLocationRepository = storageLocationRepository;
+        this.stockRepository = stockRepository;
     }
 
     public Result<StorageLocationError, StorageLocation> execute(String storageLocationId, ActorId performedBy) {
@@ -29,16 +31,24 @@ public class DeactivateStorageLocation {
             }
         }
 
-        // TODO: Stock-Existenz prüfen, wenn Stock BC implementiert ist
-        // Akzeptanzkriterium: Deaktivierung schlägt fehl, wenn Stock am Lagerort existiert
+        // 2. Stock-Existenz prüfen
+        switch (stockRepository.findAllByStorageLocationId(locationId)) {
+            case Result.Failure(var err) ->
+                    { return Result.failure(new StorageLocationError.RepositoryFailure(err.message())); }
+            case Result.Success(var stocks) -> {
+                if (!stocks.isEmpty()) {
+                    return Result.failure(new StorageLocationError.StockExistsAtLocation(storageLocationId));
+                }
+            }
+        }
 
-        // 2. Deaktivieren
+        // 3. Deaktivieren
         switch (location.deactivate()) {
             case Result.Failure(var err) -> { return Result.failure(err); }
             case Result.Success(var ignored) -> { }
         }
 
-        // 3. Speichern
+        // 4. Speichern
         switch (storageLocationRepository.save(location)) {
             case Result.Failure(var err) ->
                     { return Result.failure(new StorageLocationError.RepositoryFailure(err.message())); }
diff --git a/backend/src/test/java/de/effigenix/application/inventory/DeactivateStorageLocationTest.java b/backend/src/test/java/de/effigenix/application/inventory/DeactivateStorageLocationTest.java
new file mode 100644
index 0000000..d46e2fa
--- /dev/null
+++ b/backend/src/test/java/de/effigenix/application/inventory/DeactivateStorageLocationTest.java
@@ -0,0 +1,138 @@
+package de.effigenix.application.inventory;
+
+import de.effigenix.domain.inventory.*;
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.shared.common.RepositoryError;
+import de.effigenix.shared.common.Result;
+import de.effigenix.shared.security.ActorId;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.List;
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+@DisplayName("DeactivateStorageLocation Use Case")
+class DeactivateStorageLocationTest {
+
+    @Mock private StorageLocationRepository storageLocationRepository;
+    @Mock private StockRepository stockRepository;
+
+    private DeactivateStorageLocation deactivateStorageLocation;
+    private ActorId performedBy;
+
+    @BeforeEach
+    void setUp() {
+        deactivateStorageLocation = new DeactivateStorageLocation(storageLocationRepository, stockRepository);
+        performedBy = ActorId.of("admin-user");
+    }
+
+    private StorageLocation activeLocation(String id) {
+        return StorageLocation.reconstitute(
+                StorageLocationId.of(id),
+                new StorageLocationName("Kühlraum 1"),
+                StorageType.COLD_ROOM,
+                null,
+                true
+        );
+    }
+
+    private StorageLocation inactiveLocation(String id) {
+        return StorageLocation.reconstitute(
+                StorageLocationId.of(id),
+                new StorageLocationName("Kühlraum 1"),
+                StorageType.COLD_ROOM,
+                null,
+                false
+        );
+    }
+
+    @Test
+    @DisplayName("should deactivate active location without stock")
+    void shouldDeactivateActiveLocationWithoutStock() {
+        var locationId = StorageLocationId.of("loc-1");
+        when(storageLocationRepository.findById(locationId))
+                .thenReturn(Result.success(Optional.of(activeLocation("loc-1"))));
+        when(stockRepository.findAllByStorageLocationId(locationId))
+                .thenReturn(Result.success(List.of()));
+        when(storageLocationRepository.save(any()))
+                .thenReturn(Result.success(null));
+
+        var result = deactivateStorageLocation.execute("loc-1", performedBy);
+
+        assertThat(result.isSuccess()).isTrue();
+        assertThat(result.unsafeGetValue().active()).isFalse();
+    }
+
+    @Test
+    @DisplayName("should fail with StockExistsAtLocation when stock exists")
+    void shouldFailWhenStockExistsAtLocation() {
+        var locationId = StorageLocationId.of("loc-1");
+        var stock = Stock.reconstitute(
+                StockId.of("stock-1"), ArticleId.of("article-1"),
+                locationId, null, null, List.of()
+        );
+        when(storageLocationRepository.findById(locationId))
+                .thenReturn(Result.success(Optional.of(activeLocation("loc-1"))));
+        when(stockRepository.findAllByStorageLocationId(locationId))
+                .thenReturn(Result.success(List.of(stock)));
+
+        var result = deactivateStorageLocation.execute("loc-1", performedBy);
+
+        assertThat(result.isFailure()).isTrue();
+        assertThat(result.unsafeGetError()).isInstanceOf(StorageLocationError.StockExistsAtLocation.class);
+        verify(storageLocationRepository, never()).save(any());
+    }
+
+    @Test
+    @DisplayName("should fail with StorageLocationNotFound when location does not exist")
+    void shouldFailWhenLocationNotFound() {
+        when(storageLocationRepository.findById(StorageLocationId.of("nonexistent")))
+                .thenReturn(Result.success(Optional.empty()));
+
+        var result = deactivateStorageLocation.execute("nonexistent", performedBy);
+
+        assertThat(result.isFailure()).isTrue();
+        assertThat(result.unsafeGetError()).isInstanceOf(StorageLocationError.StorageLocationNotFound.class);
+    }
+
+    @Test
+    @DisplayName("should fail with AlreadyInactive when location is already inactive")
+    void shouldFailWhenAlreadyInactive() {
+        var locationId = StorageLocationId.of("loc-1");
+        when(storageLocationRepository.findById(locationId))
+                .thenReturn(Result.success(Optional.of(inactiveLocation("loc-1"))));
+        when(stockRepository.findAllByStorageLocationId(locationId))
+                .thenReturn(Result.success(List.of()));
+
+        var result = deactivateStorageLocation.execute("loc-1", performedBy);
+
+        assertThat(result.isFailure()).isTrue();
+        assertThat(result.unsafeGetError()).isInstanceOf(StorageLocationError.AlreadyInactive.class);
+    }
+
+    @Test
+    @DisplayName("should fail with RepositoryFailure when stock repository fails")
+    void shouldFailWhenStockRepositoryFails() {
+        var locationId = StorageLocationId.of("loc-1");
+        when(storageLocationRepository.findById(locationId))
+                .thenReturn(Result.success(Optional.of(activeLocation("loc-1"))));
+        when(stockRepository.findAllByStorageLocationId(locationId))
+                .thenReturn(Result.failure(new RepositoryError.DatabaseError("connection lost")));
+
+        var result = deactivateStorageLocation.execute("loc-1", performedBy);
+
+        assertThat(result.isFailure()).isTrue();
+        assertThat(result.unsafeGetError()).isInstanceOf(StorageLocationError.RepositoryFailure.class);
+    }
+}