Preheat oven to 450 degrees F. Place potatoes, chili powder, salt, pepper, and oil in plastic bag. Shake vigorously to coat potatoes evenly with all ingredients. Spread out on a cookie sheet. Do not over crowd or overlap potatoes or they will steam. Bake 20 to 25 minutes, turning once, until golden and cooked through.
Remove from oven and let stand 5 minutes. They will come off tray easily.