The 1990 Winston 200 was the fourth race of the 1990 NASCAR Winston West Series season. The race was held on Sunday, July 1, 1990, at Portland Speedway, a 0.500 mi (0.805 km) oval shaped racetrack in Portland, Oregon. The race took the scheduled 200 laps to complete. The race was won by Roy Smith, his first win of the season. Smith was not in contention for the win until after his second and final pit stop, where he moved into second before passing Bill Sedgwick for the lead with 23 laps remaining. Bill Schmitt passed Sedgwick finished second, relegating Sedgwick to a third place finish. 1990 Daytona 500 winner Derrike Cope finished fourth in what would be his final West Series start, and Butch Gilliland rounded out the top five.

Portland Speedway was a half-mile race track for auto racing in Portland, Oregon. It was in existence from 1924 until 2001. It hosted 55 races for the West Series between 1956 and 2000.

Mike Chase won the pole with a speed of 86.963 mph.