diff --git a/src/BackOffice.BFF.Application/Common/Interfaces/IApplicationContractContext.cs b/src/BackOffice.BFF.Application/Common/Interfaces/IApplicationContractContext.cs
index 494169d..89562dd 100644
--- a/src/BackOffice.BFF.Application/Common/Interfaces/IApplicationContractContext.cs
+++ b/src/BackOffice.BFF.Application/Common/Interfaces/IApplicationContractContext.cs
@@ -8,6 +8,7 @@ using CMSMicroservice.Protobuf.Protos.Products;
 using CMSMicroservice.Protobuf.Protos.ProductImages;
 using CMSMicroservice.Protobuf.Protos.ProductGallerys;
 using CMSMicroservice.Protobuf.Protos.Category;
+using CMSMicroservice.Protobuf.Protos.PruductCategory;
 using FMSMicroservice.Protobuf.Protos.FileInfo;
 
 namespace BackOffice.BFF.Application.Common.Interfaces;
@@ -24,6 +25,7 @@ public interface IApplicationContractContext
     ProductGallerysContract.ProductGallerysContractClient ProductGallerys { get; }
     RoleContract.RoleContractClient Roles { get; }
     CategoryContract.CategoryContractClient Categories { get; }
+    PruductCategoryContract.PruductCategoryContractClient ProductCategories { get; }
     UserAddressContract.UserAddressContractClient UserAddress { get; }
     UserContract.UserContractClient Users { get; }
     UserOrderContract.UserOrderContractClient UserOrders { get; }
diff --git a/src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommandHandler.cs b/src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommandHandler.cs
index 802d634..3ec7813 100644
--- a/src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommandHandler.cs
+++ b/src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommandHandler.cs
@@ -1,4 +1,5 @@
 using BackOffice.BFF.Application.Common.Interfaces;
+using CMSPruductCategory = CMSMicroservice.Protobuf.Protos.PruductCategory;
 
 namespace BackOffice.BFF.Application.ProductsCQ.Commands.UpdateProductCategories;
 
@@ -13,9 +14,49 @@ public class UpdateProductCategoriesCommandHandler : IRequestHandler<UpdateProdu
 
     public async Task<Unit> Handle(UpdateProductCategoriesCommand request, CancellationToken cancellationToken)
     {
-        // Stub: until CMS Category services are available via the protobuf package,
-        // this handler is a no-op to keep the pipeline consistent.
-        await Task.CompletedTask;
+        var targetIds = request.CategoryIds?.ToHashSet() ?? new HashSet<long>();
+
+        // Load existing product-category relations
+        var existingRequest = new CMSPruductCategory.GetAllPruductCategoryByFilterRequest
+        {
+            Filter = new CMSPruductCategory.GetAllPruductCategoryByFilterFilter
+            {
+                ProductId = request.ProductId
+            },
+            PaginationState = new CMSMicroservice.Protobuf.Protos.PaginationState
+            {
+                PageNumber = 1,
+                PageSize = 1000
+            }
+        };
+
+        var existingResponse = await _context.ProductCategories.GetAllPruductCategoryByFilterAsync(existingRequest, cancellationToken: cancellationToken);
+        var existing = existingResponse.Models ?? new();
+
+        var existingIds = existing.Select(x => x.CategoryId).ToHashSet();
+
+        // Determine which relations to add and which to remove
+        var toAdd = targetIds.Except(existingIds).ToList();
+        var toRemove = existing.Where(x => !targetIds.Contains(x.CategoryId)).ToList();
+
+        foreach (var categoryId in toAdd)
+        {
+            var createRequest = new CMSPruductCategory.CreateNewPruductCategoryRequest
+            {
+                ProductId = request.ProductId,
+                CategoryId = categoryId
+            };
+
+            await _context.ProductCategories.CreateNewPruductCategoryAsync(createRequest, cancellationToken: cancellationToken);
+        }
+
+        foreach (var rel in toRemove)
+        {
+            await _context.ProductCategories.DeletePruductCategoryAsync(
+                new CMSPruductCategory.DeletePruductCategoryRequest { Id = rel.Id },
+                cancellationToken: cancellationToken);
+        }
+
         return Unit.Value;
     }
 }
diff --git a/src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQueryHandler.cs b/src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQueryHandler.cs
index d7cb1c7..977706f 100644
--- a/src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQueryHandler.cs
+++ b/src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQueryHandler.cs
@@ -1,20 +1,67 @@
 using BackOffice.BFF.Application.Common.Interfaces;
+using CMSCategory = CMSMicroservice.Protobuf.Protos.Category;
+using CMSPruductCategory = CMSMicroservice.Protobuf.Protos.PruductCategory;
 
 namespace BackOffice.BFF.Application.ProductsCQ.Queries.GetCategories;
 
 public class GetCategoriesQueryHandler : IRequestHandler<GetCategoriesQuery, GetCategoriesResponseDto>
 {
+    private readonly IApplicationContractContext _context;
+
     public GetCategoriesQueryHandler(IApplicationContractContext context)
     {
-        // context is currently unused; reserved for future CMS integration
+        _context = context;
     }
 
     public async Task<GetCategoriesResponseDto> Handle(GetCategoriesQuery request, CancellationToken cancellationToken)
     {
-        // Stub implementation: returns empty list.
-        // When CMS protobuf package with Category support is available,
-        // this handler can be updated to call Category and PruductCategory services.
-        await Task.CompletedTask;
-        return new GetCategoriesResponseDto();
+        // Load all categories
+        var categoryRequest = new CMSCategory.GetAllCategoryByFilterRequest
+        {
+            Filter = new CMSCategory.GetAllCategoryByFilterFilter(),
+            PaginationState = new CMSMicroservice.Protobuf.Protos.PaginationState
+            {
+                PageNumber = 1,
+                PageSize = 1000
+            }
+        };
+
+        var categoriesResponse = await _context.Categories.GetAllCategoryByFilterAsync(categoryRequest, cancellationToken: cancellationToken);
+        var categories = categoriesResponse.Models ?? new();
+
+        // Load existing product-category relations for this product
+        var productCategoryRequest = new CMSPruductCategory.GetAllPruductCategoryByFilterRequest
+        {
+            Filter = new CMSPruductCategory.GetAllPruductCategoryByFilterFilter
+            {
+                ProductId = request.ProductId
+            },
+            PaginationState = new CMSMicroservice.Protobuf.Protos.PaginationState
+            {
+                PageNumber = 1,
+                PageSize = 1000
+            }
+        };
+
+        var productCategoriesResponse = await _context.ProductCategories.GetAllPruductCategoryByFilterAsync(productCategoryRequest, cancellationToken: cancellationToken);
+        var productCategories = productCategoriesResponse.Models ?? new();
+
+        var selectedIds = productCategories
+            .Select(pc => pc.CategoryId)
+            .ToHashSet();
+
+        var result = new GetCategoriesResponseDto
+        {
+            Items = categories
+                .Select(c => new CategoryItemDto
+                {
+                    Id = c.Id,
+                    Title = c.Title,
+                    Selected = selectedIds.Contains(c.Id)
+                })
+                .ToList()
+        };
+
+        return result;
     }
 }
diff --git a/src/BackOffice.BFF.Infrastructure/Services/ApplicationContractContext.cs b/src/BackOffice.BFF.Infrastructure/Services/ApplicationContractContext.cs
index 298f8da..1e5c3f5 100644
--- a/src/BackOffice.BFF.Infrastructure/Services/ApplicationContractContext.cs
+++ b/src/BackOffice.BFF.Infrastructure/Services/ApplicationContractContext.cs
@@ -9,6 +9,7 @@ using CMSMicroservice.Protobuf.Protos.Products;
 using CMSMicroservice.Protobuf.Protos.ProductImages;
 using CMSMicroservice.Protobuf.Protos.ProductGallerys;
 using CMSMicroservice.Protobuf.Protos.Category;
+using CMSMicroservice.Protobuf.Protos.PruductCategory;
 using FMSMicroservice.Protobuf.Protos.FileInfo;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -48,6 +49,7 @@ public class ApplicationContractContext : IApplicationContractContext
     public ProductGallerysContract.ProductGallerysContractClient ProductGallerys => GetService<ProductGallerysContract.ProductGallerysContractClient>();
     public RoleContract.RoleContractClient Roles => GetService<RoleContract.RoleContractClient>();
     public CategoryContract.CategoryContractClient Categories => GetService<CategoryContract.CategoryContractClient>();
+    public PruductCategoryContract.PruductCategoryContractClient ProductCategories => GetService<PruductCategoryContract.PruductCategoryContractClient>();
     public UserAddressContract.UserAddressContractClient UserAddress => GetService<UserAddressContract.UserAddressContractClient>();
     public UserContract.UserContractClient Users => GetService<UserContract.UserContractClient>();
     public UserOrderContract.UserOrderContractClient UserOrders => GetService<UserOrderContract.UserOrderContractClient>();