Begin by prepping and measuring out all ingredients.
Place margarine in a pot over medium-high heat. Allow to melt then add sugar, cocoa, and milk. Mix well with a mixing spoon.
Keep mixing and allow to cook, continually mixing so the mixture doesn't scald. As soon as it starts to boil, remove from heat and add vanilla, peanut butter, and oats. Combine.
Spoon onto wax paper and allow to cool.