diff --git a/trytond/backend/mysql/database.py b/trytond/backend/mysql/database.py
index 38ef54ebb8..9f55458c6d 100644
--- a/trytond/backend/mysql/database.py
+++ b/trytond/backend/mysql/database.py
@@ -131,7 +131,7 @@ class Database(DatabaseInterface):
         if uri.hostname:
             cmd.append('--host=' + uri.hostname)
         if uri.port:
-            cmd.append('--port=' + uri.port)
+            cmd.append('--port=' + str(uri.port))
         if uri.password:
             cmd.append('--password=' + uri.password)
         cmd.append(database_name)
@@ -161,7 +161,7 @@ class Database(DatabaseInterface):
         if uri.hostname:
             cmd.append('--host=' + uri.hostname)
         if uri.port:
-            cmd.append('--port=' + uri.port)
+            cmd.append('--port=' + str(uri.port))
         if uri.password:
             cmd.append('--password=' + uri.password)
         cmd.append(database_name)
diff --git a/trytond/backend/postgresql/database.py b/trytond/backend/postgresql/database.py
index c42e6cce14..2bbeca37af 100644
--- a/trytond/backend/postgresql/database.py
+++ b/trytond/backend/postgresql/database.py
@@ -117,7 +117,7 @@ class Database(DatabaseInterface):
         if uri.hostname:
             cmd.append('--host=' + uri.hostname)
         if uri.port:
-            cmd.append('--port=' + uri.port)
+            cmd.append('--port=' + str(uri.port))
         if uri.password:
             # if db_password is set in configuration we should pass
             # an environment variable PGPASSWORD to our subprocess
@@ -151,7 +151,7 @@ class Database(DatabaseInterface):
         if uri.hostname:
             cmd.append('--host=' + uri.hostname)
         if uri.port:
-            cmd.append('--port=' + uri.port)
+            cmd.append('--port=' + str(uri.port))
         if uri.password:
             env['PGPASSWORD'] = uri.password
         cmd.append('--dbname=' + database_name)