Pour the cake mix into a large bowl. Make a well in the center, and add peanut butter, oil, eggs, and water. Mix until well blended. Drop by teaspoonfuls onto ungreased cookie sheets. Flatten slightly using a fork dipped in water.
Bake for 10 to 12 minutes in the preheated oven. Let cookies set on cookie sheet for 2 to 3 minutes before carefully removing from the cookie sheet to cool on wire racks.