diff --git a/modules/invoiceIn/back/models/invoice-in-tax.js b/modules/invoiceIn/back/models/invoice-in-tax.js
new file mode 100644
index 000000000..a9d16ec42
--- /dev/null
+++ b/modules/invoiceIn/back/models/invoice-in-tax.js
@@ -0,0 +1,18 @@
+const UserError = require('vn-loopback/util/user-error');
+
+module.exports = Self => {
+    Self.observe('before save', async function(ctx) {
+        if (ctx.newInstance) return;
+
+        const models = Self.app.models;
+        const invoiceIn = await models.InvoiceIn.findById(ctx.currentInstance.invoiceInFk);
+        if (invoiceIn.isBooked) throw new UserError('InvoiceIn is already booked');
+    });
+
+    Self.observe('before delete', async function(ctx) {
+        const models = Self.app.models;
+        const invoiceInTax = await models.InvoiceInTax.findById(ctx.where.id);
+        const invoiceIn = await models.InvoiceIn.findById(invoiceInTax.invoiceInFk);
+        if (invoiceIn.isBooked) throw new UserError('InvoiceIn is already booked');
+    });
+};
diff --git a/modules/invoiceIn/back/models/invoice-in.js b/modules/invoiceIn/back/models/invoice-in.js
index 21aa230c5..ff5d1ba86 100644
--- a/modules/invoiceIn/back/models/invoice-in.js
+++ b/modules/invoiceIn/back/models/invoice-in.js
@@ -34,4 +34,10 @@ module.exports = Self => {
             }
         }
     });
+
+    Self.observe('before delete', async function(ctx) {
+        const invoiceIn = await Self.findById(ctx.where.id);
+        if (invoiceIn.isBooked) throw new UserError('InvoiceIn is already booked');
+    });
 };
+