diff --git a/cmd/web/router/routes.go b/cmd/web/router/routes.go
index a274432..4ed6820 100644
--- a/cmd/web/router/routes.go
+++ b/cmd/web/router/routes.go
@@ -82,6 +82,7 @@ func RegisterAdminRoutes(e *echo.Echo, userHandler *user.Handler, companyHandler
 		customersGP.DELETE("/:id", customerHandler.DeleteCustomer)
 		customersGP.PUT("/:id/status", customerHandler.UpdateStatus)
 		customersGP.PATCH("/:id/role", customerHandler.AssignRole)
+		customersGP.PATCH("/:id/companies", customerHandler.AssignCompanies)
 	}
 
 	// Admin Tenders Routes
diff --git a/internal/customer/handler.go b/internal/customer/handler.go
index 9d3c8d2..da26268 100644
--- a/internal/customer/handler.go
+++ b/internal/customer/handler.go
@@ -265,6 +265,37 @@ func (h *Handler) AssignRole(c echo.Context) error {
 	return response.Success(c, result, "Role assigned successfully")
 }
 
+// AssignCompanies assigns companies to a customer
+// @Summary Assign companies to a customer
+// @Description Assign companies to a customer
+// @Tags Admin-Customers
+// @Accept json
+// @Produce json
+// @Param id path string true "Customer ID"
+// @Param companies body AssignCompaniesForm true "Companies to assign"
+// @Success 200 {object} response.APIResponse "Companies assigned successfully"
+// @Failure 400 {object} response.APIResponse "Bad request - Invalid input data"
+// @Failure 422 {object} response.APIResponse "Validation error - Invalid request data"
+// @Failure 500 {object} response.APIResponse "Internal server error"
+// @Security BearerAuth
+// @Router /admin/v1/customers/{id}/companies [patch]
+func (h *Handler) AssignCompanies(c echo.Context) error {
+	id := c.Param("id")
+	form, err := response.Parse[AssignCompaniesForm](c)
+	if err != nil {
+		return response.ValidationError(c, "Invalid request data", err.Error())
+	}
+
+	err = h.service.AssignCompanies(c.Request().Context(), id, form.Companies)
+	if err != nil {
+		return response.InternalServerError(c, "Failed to assign companies to customer")
+	}
+
+	return response.Success(c, map[string]interface{}{
+		"message": "Companies assigned successfully",
+	}, "Companies assigned successfully")
+}
+
 // **************************************************
 // *                 PROFILE HANDLERS               *
 // **************************************************
diff --git a/internal/customer/service.go b/internal/customer/service.go
index 0109ab1..ca3af1a 100644
--- a/internal/customer/service.go
+++ b/internal/customer/service.go
@@ -46,6 +46,7 @@ type Service interface {
 
 	// Role assignment operations
 	AssignRole(ctx context.Context, customerID string, form *AssignRoleForm) (*AssignRoleResponse, error)
+	AssignCompanies(ctx context.Context, customerID string, Companies []string) error
 }
 
 // customerService implements the Service interface
@@ -360,6 +361,7 @@ func (s *customerService) AssignCompanies(ctx context.Context, customerID string
 	}
 
 	// Update customer's company IDs
+	customer.Companies = make([]string, 0)
 	customer.Companies = append(customer.Companies, validCompanies...)
 	customer.UpdatedAt = time.Now().Unix()
 
@@ -380,7 +382,7 @@ func (s *customerService) AssignCompanies(ctx context.Context, customerID string
 	return nil
 }
 
-// RemoveCompaniesFromCustomer removes companies from a customer
+// RemoveCompanies removes companies from a customer
 func (s *customerService) RemoveCompanies(ctx context.Context, customerID string, Companies []string) error {
 	// Get customer to check if exists
 	customer, err := s.repository.GetByID(ctx, customerID)
@@ -409,7 +411,7 @@ func (s *customerService) RemoveCompanies(ctx context.Context, customerID string
 
 	err = s.repository.Update(ctx, customer)
 	if err != nil {
-		s.logger.Error("Failed to update customer after removing company assignments", map[string]interface{}{
+		s.logger.Error("Failed to update customer after removing companies", map[string]interface{}{
 			"error":       err.Error(),
 			"customer_id": customerID,
 		})