diff --git a/dlt/destinations/mssql/configuration.py b/dlt/destinations/mssql/configuration.py
index 581da0f782..17f10ddff0 100644
--- a/dlt/destinations/mssql/configuration.py
+++ b/dlt/destinations/mssql/configuration.py
@@ -60,8 +60,7 @@ def _get_odbc_driver(self) -> str:
     def to_odbc_dsn(self) -> str:
         params = {
             "DRIVER": self.odbc_driver,
-            "SERVER": self.host,
-            "PORT": self.port,
+            "SERVER": f"{self.host},{self.port}",
             "DATABASE": self.database,
             "UID": self.username,
             "PWD": self.password,
diff --git a/tests/load/mssql/test_mssql_credentials.py b/tests/load/mssql/test_mssql_credentials.py
new file mode 100644
index 0000000000..9b57692bb2
--- /dev/null
+++ b/tests/load/mssql/test_mssql_credentials.py
@@ -0,0 +1,24 @@
+from dlt.common.configuration import resolve_configuration
+
+from dlt.destinations.mssql.configuration import MsSqlCredentials
+
+
+
+def test_to_odbc_dsn() -> None:
+    creds = resolve_configuration(
+        MsSqlCredentials("mssql://test_user:test_password@sql.example.com:12345/test_db?FOO=a&BAR=b")
+    )
+
+    dsn = creds.to_odbc_dsn()
+
+    result = {k: v for k, v in (param.split('=') for param in dsn.split(";"))}
+
+    assert result == {
+        'DRIVER': 'ODBC Driver 18 for SQL Server',
+        'SERVER': 'sql.example.com,12345',
+        'DATABASE': 'test_db',
+        'UID': 'test_user',
+        'PWD': 'test_password',
+        'FOO': 'a',
+        'BAR': 'b'
+    }