Heat oven to 350ยบ. Grease a 9x13 inch pan. Set aside.
In a medium bowl, combine graham cracker crumbs and melted butter. Stir well to combine. Press mixture into the bottom of the greased pan, packing tightly with the back of a spoon.
Pour entire can of sweetened condensed milk over crust.
Evenly spread chopped pecans, crushed Oreos and whole M&M's over sweetened condensed milk. Press down firmly on toppings with the back of a spoon.
Bake 25 minutes. Remove from oven and cool thoroughly before slicing.