Preheat oven to 175 degrees C. Sift together flour, baking powder, baking soda, and salt; set a side.
In a medium bowl, cream margarine, oil, brown sugar, and white sugar until smooth. Beat in eggs one at a time. Stir in the sifted ingredients until well blended. Mix in oats. Drop from a teaspoon onto cookie sheets.
Bake for 10 to 12 minutes in oven, or until edges are golden. Let set up on the cookie sheets for a few minutes before transferring to wire racks to cool completely.