Preheat the oven to 350 F. In a large bowl, mix together cake mix, oatmeal, eggs, and vegetable oil until smooth. In a shallow dish, place the powdered sugar.
Roll the cookie dough into balls, then roll each one into the dish of powdered sugar. Place the cookies onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.