diff --git a/internal/customer/handler.go b/internal/customer/handler.go
index 5431089..b7c4de2 100644
--- a/internal/customer/handler.go
+++ b/internal/customer/handler.go
@@ -55,6 +55,7 @@ func (h *Handler) CreateCustomer(c echo.Context) error {
 	if err != nil {
 		if err.Error() == "customer with this email already exists" ||
 			err.Error() == "customer with this username already exists" ||
+			err.Error() == "customer with this phone number already exists" ||
 			err.Error() == "company with this name already exists" ||
 			err.Error() == "company with this registration number already exists" ||
 			err.Error() == "company with this tax ID already exists" {
@@ -128,6 +129,7 @@ func (h *Handler) UpdateCustomer(c echo.Context) error {
 		}
 		if err.Error() == "customer with this email already exists" ||
 			err.Error() == "customer with this username already exists" ||
+			err.Error() == "customer with this phone number already exists" ||
 			err.Error() == "company with this name already exists" ||
 			err.Error() == "company with this registration number already exists" ||
 			err.Error() == "company with this tax ID already exists" {
diff --git a/internal/customer/repository.go b/internal/customer/repository.go
index ed52842..cc557d4 100644
--- a/internal/customer/repository.go
+++ b/internal/customer/repository.go
@@ -25,6 +25,7 @@ type Repository interface {
 	GetByID(ctx context.Context, id string) (*Customer, error)
 	GetByEmail(ctx context.Context, email string) (*Customer, error)
 	GetByUsername(ctx context.Context, username string) (*Customer, error)
+	GetByPhone(ctx context.Context, phone string) (*Customer, error)
 	GetByIDs(ctx context.Context, ids []string) ([]Customer, error)
 	GetByRole(ctx context.Context, role CustomerRole) ([]Customer, error)
 	GetByCompanies(ctx context.Context, companies []string) ([]Customer, error)
@@ -50,6 +51,8 @@ func NewRepository(mongoManager *orm.ConnectionManager, logger logger.Logger) Re
 	indexes := []orm.Index{
 		*orm.CreateUniqueIndex("username_idx", bson.D{{Key: "username", Value: 1}}),
 		*orm.CreateTextIndex("search_idx", "email", "username"),
+		*orm.CreateUniqueIndex("phone_idx", bson.D{{Key: "phone", Value: 1}}).
+			WithPartialFilterExpression(bson.M{"phone": bson.M{"$type": "string", "$ne": ""}}),
 	}
 
 	// Create indexes
@@ -166,6 +169,24 @@ func (r *customerRepository) GetByEmail(ctx context.Context, email string) (*Cus
 	return customer, nil
 }
 
+// GetByPhone retrieves a customer by phone number
+func (r *customerRepository) GetByPhone(ctx context.Context, phone string) (*Customer, error) {
+	filter := bson.M{"phone": phone}
+	customer, err := r.ormRepo.FindOne(ctx, filter)
+	if err != nil {
+		if errors.Is(err, orm.ErrDocumentNotFound) {
+			return nil, ErrCustomerNotFound
+		}
+		r.logger.Error("Failed to get customer by phone", map[string]interface{}{
+			"error": err.Error(),
+			"phone": phone,
+		})
+		return nil, err
+	}
+
+	return customer, nil
+}
+
 // GetByUsername retrieves a customer by username
 func (r *customerRepository) GetByUsername(ctx context.Context, username string) (*Customer, error) {
 	filter := bson.M{"username": username}
diff --git a/internal/customer/service.go b/internal/customer/service.go
index a75b4fc..3a88166 100644
--- a/internal/customer/service.go
+++ b/internal/customer/service.go
@@ -95,6 +95,13 @@ func (s *customerService) Register(ctx context.Context, form *CreateCustomerForm
 		return nil, errors.New("customer with this username already exists")
 	}
 
+	if form.Phone != nil && *form.Phone != "" {
+		existingCustomer, _ = s.repository.GetByPhone(ctx, *form.Phone)
+		if existingCustomer != nil {
+			return nil, errors.New("customer with this phone number already exists")
+		}
+	}
+
 	// Check validator
 	if !s.validator.IsValidUsername(form.Username) {
 		return nil, errors.New("invalid username format")
@@ -373,6 +380,12 @@ func (s *customerService) Update(ctx context.Context, id string, form *UpdateCus
 	}
 
 	if form.Phone != nil && (customer.Phone == nil || *form.Phone != *customer.Phone) {
+		if *form.Phone != "" {
+			existingCustomer, _ := s.repository.GetByPhone(ctx, *form.Phone)
+			if existingCustomer != nil && existingCustomer.ID.Hex() != id {
+				return nil, errors.New("customer with this phone number already exists")
+			}
+		}
 		customer.Phone = form.Phone
 		infoChanged = true
 	}
diff --git a/internal/user/repository.go b/internal/user/repository.go
index 09796d3..e758a4b 100644
--- a/internal/user/repository.go
+++ b/internal/user/repository.go
@@ -22,6 +22,7 @@ type Repository interface {
 	UpdatePasswordReset(ctx context.Context, id, hashedPassword, updatedBy string) error
 	GetByEmail(ctx context.Context, email string) (*User, error)
 	GetByUsername(ctx context.Context, username string) (*User, error)
+	GetByPhone(ctx context.Context, phone string) (*User, error)
 	GetByIDs(ctx context.Context, userIDs []string) ([]User, error)
 	Search(ctx context.Context, form *SearchUsersForm, pagination *response.Pagination) (*orm.PaginatedResult[User], error)
 }
@@ -38,6 +39,8 @@ func NewRepository(mongoManager *orm.ConnectionManager, logger logger.Logger) Re
 	// Create indexes using the ORM's index management
 	indexes := []orm.Index{
 		*orm.CreateTextIndex("search_idx", "full_name", "email", "username"),
+		*orm.CreateUniqueIndex("phone_idx", bson.D{{Key: "phone", Value: 1}}).
+			WithPartialFilterExpression(bson.M{"phone": bson.M{"$type": "string", "$ne": ""}}),
 	}
 
 	// Create indexes
@@ -250,6 +253,23 @@ func (r *userRepository) GetByEmail(ctx context.Context, email string) (*User, e
 	return user, nil
 }
 
+// GetByPhone retrieves a user by phone number
+func (r *userRepository) GetByPhone(ctx context.Context, phone string) (*User, error) {
+	user, err := r.ormRepo.FindOne(ctx, bson.M{"phone": phone})
+	if err != nil {
+		if errors.Is(err, orm.ErrDocumentNotFound) {
+			return nil, errors.New("user not found")
+		}
+		r.logger.Error("Failed to get user by phone", map[string]interface{}{
+			"error": err.Error(),
+			"phone": phone,
+		})
+		return nil, err
+	}
+
+	return user, nil
+}
+
 // GetByUsername retrieves a user by username
 func (r *userRepository) GetByUsername(ctx context.Context, username string) (*User, error) {
 	user, err := r.ormRepo.FindOne(ctx, bson.M{"username": username})
diff --git a/internal/user/service.go b/internal/user/service.go
index fbfac0b..8bc6c4d 100644
--- a/internal/user/service.go
+++ b/internal/user/service.go
@@ -77,6 +77,13 @@ func (s *userService) Register(ctx context.Context, form *CreateUserForm) (*User
 		return nil, errors.New("username already exists")
 	}
 
+	if form.Phone != nil && *form.Phone != "" {
+		existingUser, _ = s.repository.GetByPhone(ctx, *form.Phone)
+		if existingUser != nil {
+			return nil, errors.New("phone number already exists")
+		}
+	}
+
 	// Hash password
 	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(form.Password), bcrypt.DefaultCost)
 	if err != nil {
@@ -185,6 +192,12 @@ func (s *userService) Update(ctx context.Context, id string, form *UpdateUserFor
 	}
 
 	if form.Phone != nil {
+		if *form.Phone != "" {
+			existingUser, _ := s.repository.GetByPhone(ctx, *form.Phone)
+			if existingUser != nil && existingUser.ID.Hex() != id {
+				return nil, errors.New("phone number already exists")
+			}
+		}
 		user.Phone = form.Phone
 	}
 
@@ -574,6 +587,12 @@ func (s *userService) UpdateProfile(ctx context.Context, userID string, form *Up
 		user.Position = form.Position
 	}
 	if form.Phone != nil {
+		if *form.Phone != "" {
+			existingUser, _ := s.repository.GetByPhone(ctx, *form.Phone)
+			if existingUser != nil && existingUser.ID.Hex() != userID {
+				return errors.New("phone number already exists")
+			}
+		}
 		user.Phone = form.Phone
 	}
 	if form.ProfileImage != nil {