The company had sold 85,565 units in the same month last year.
In September, MSI recorded a domestic sales of 88,801 units compared to 78,816 units in the year-ago period, registering a rise of 12.67 per cent, the company said in a statement.
However, MSI's exports went down 23.14 per cent to 5,187 units last month from 6,749 units in the year-ago period, it said.
Total passenger car sales in the domestic market rose by 3.43 per cent to 68,957 units from 66,667 units in the same month of 2011, it added.
Sales of the company's mini-segment cars, including M800, A-Star [ Images ], Alto [ Images ] and WagonR [ Images ], increased by 4.89 per cent to 39,150 units during the month from 37,324 units in September last year.
However, in the compact segment (comprising the Estilo, Swift [ Images ] and Ritz models), MSI witnessed a 9.68 per cent fall in sales to 17,813 units from 19,722 units in the same month a year ago.
Sales of MSI's DZiRE [ Images ] model increased by 24.26 per cent to 11,694 units in September from 9,411 units in the same month last year.
MSI's mid-sized sedan SX4 [ Images ] sales were up 46.94 per cent to 288 units last month from 196 units in September 2011.
Luxury sedan Kizashi witnessed 14.29 per cent fall in sales at 12 units as against 14 units in the year-ago month.