The 1990 du Maurier Classic was contested from June 28 to July 1 at Westmount Golf & Country Club. It was the 18th edition of the du Maurier Classic, and the 12th edition as a major championship on the LPGA Tour.
This event was won by Cathy Johnston-Forbes.
Coordinates: 43°27′09″N 80°32′13″W / 43.45242°N 80.536852°W