diff --git a/addons/account/models/account_invoice.py b/addons/account/models/account_invoice.py
index 8d73a1f5c85..06fba95630c 100644
--- a/addons/account/models/account_invoice.py
+++ b/addons/account/models/account_invoice.py
@@ -1310,6 +1310,9 @@ class AccountInvoiceLine(models.Model):
                 self.price_unit = 0.0
             domain['uom_id'] = []
         else:
+            # Use the purchase uom by default
+            self.uom_id = self.product_id.uom_po_id
+
             if part.lang:
                 product = self.product_id.with_context(lang=part.lang)
             else: