diff --git a/loopback/locale/en.json b/loopback/locale/en.json
index b10ea2e71..c22aeb311 100644
--- a/loopback/locale/en.json
+++ b/loopback/locale/en.json
@@ -208,6 +208,6 @@
 	"the plate does not exist": "The plate {{plate}} does not exist",
 	"This pallet does not exist": "This pallet does not exist",
 	"We do not have availability for the selected item": "We do not have availability for the selected item",
-	"You are already using a machine": "You are already using a machine"
-
+	"You are already using a machine": "You are already using a machine",
+	"This worker does not exist": "This worker does not exist"
 }
\ No newline at end of file
diff --git a/loopback/locale/es.json b/loopback/locale/es.json
index c704cb8fd..e5293d856 100644
--- a/loopback/locale/es.json
+++ b/loopback/locale/es.json
@@ -345,5 +345,6 @@
 	"This pallet does not exist": "Este palet no existe",
 	"We do not have availability for the selected item": "No tenemos disponible el item seleccionado",
 	"You are already using a machine": "Ya estás usando una máquina.",
-	"Ya estás usando una máquina.": "Ya estás usando una máquina."
+	"This worker does not exist": "Este trabajador no existe",
+	"Este trabajador no existe": "Este trabajador no existe"
 }
\ No newline at end of file
diff --git a/modules/worker/back/methods/operator/add.js b/modules/worker/back/methods/operator/add.js
index eaf74e7b4..d330bc25b 100644
--- a/modules/worker/back/methods/operator/add.js
+++ b/modules/worker/back/methods/operator/add.js
@@ -1,3 +1,4 @@
+const UserError = require('vn-loopback/util/user-error');
 module.exports = Self => {
     Self.remoteMethodCtx('add', {
         description: 'Add a new operator',
@@ -8,13 +9,28 @@ module.exports = Self => {
         }
     });
 
-    Self.add = async ctx => {
+    Self.add = async(ctx, options) => {
         const userId = ctx.req.accessToken.userId;
-        const user = await Self.findById(userId);
-        if (!user) {
+        const myOptions = {};
+        const $t = ctx.req.__;
+        let tx;
+
+        if (typeof options == 'object')
+            Object.assign(myOptions, options);
+
+        if (!myOptions.transaction) {
+            tx = await Self.beginTransaction({});
+            myOptions.transaction = tx;
+        }
+
+        try {
             await Self.create({
                 workerFk: userId
             });
+            if (tx) await tx.commit();
+        } catch (e) {
+            if (tx) await tx.rollback();
+            throw new UserError($t('This worker does not exist'));
         }
     };
 };
diff --git a/modules/worker/back/methods/operator/spec/add.spec.js b/modules/worker/back/methods/operator/spec/add.spec.js
new file mode 100644
index 000000000..c2b244ada
--- /dev/null
+++ b/modules/worker/back/methods/operator/spec/add.spec.js
@@ -0,0 +1,28 @@
+const {models} = require('vn-loopback/server/server');
+
+describe('operator add()', () => {
+    beforeAll(async() => {
+        ctx = {
+            req: {
+                accessToken: {userId: 100000},
+                headers: {origin: 'http://localhost'},
+                __: value => value
+            }
+        };
+    });
+
+    it('should throw an error if the worker does not exist', async() => {
+        const tx = await models.Operator.beginTransaction({});
+        const options = {transaction: tx};
+
+        try {
+            await models.Operator.add(ctx, options);
+            await tx.rollback();
+        } catch (e) {
+            const error = e;
+
+            expect(error.message).toEqual('This worker does not exist');
+            await tx.rollback();
+        }
+    });
+});