diff --git a/backend/internal/api/handlers/product.go b/backend/internal/api/handlers/product.go
index ed852ce..65ea7e8 100644
--- a/backend/internal/api/handlers/product.go
+++ b/backend/internal/api/handlers/product.go
@@ -20,9 +20,9 @@ func NewCategoryHandler() *CategoryHandler {
 
 func (h *CategoryHandler) List(c *gin.Context) {
 	var categories []models.Category
-	utils.DB.Where("parent_id IS NULL").Order("sort_order ASC, id ASC").Find(&categories)
+	utils.DB.Where("parent_id IS NULL").Order("sort_order ASC, id ASC").Preload("PurchaseGroup").Find(&categories)
 	for i := range categories {
-		utils.DB.Where("parent_id = ?", categories[i].ID).Order("sort_order ASC, id ASC").Find(&categories[i].Children)
+		utils.DB.Where("parent_id = ?", categories[i].ID).Order("sort_order ASC, id ASC").Preload("PurchaseGroup").Find(&categories[i].Children)
 		var count int64
 		utils.DB.Table("product_categories").Where("category_id = ?", categories[i].ID).Count(&count)
 		categories[i].ProductCount = count