Preheat the oven to 170 degrees C. Grease baking trays.
In a large bowl, cream together the margarine and brown sugar until light and fluffy. Beat in the egg and water. Beat in cake mix until well blended, then stir in the oats and chocolate chips. Drop by rounded spoonfuls onto the prepared baking trays.
Bake for 8 to 10 minutes in the preheated oven. Allow biscuits to cool on baking tray for 5 minutes before removing to a wire rack to cool completely.