Preheat the oven to 325 degrees F (165 degrees C).
Dump strawberry pie filling into a 9x12 inch baking dish. Sprinkle with blueberries. Pour cake mix on top of blueberries. Drizzle melted butter on top.
Bake in the preheated oven until the top is a light golden brown, about 45 minutes. Serve warm.
Red, White, and Blue Dump Cake · Dinner Match Lab | Dinner Match Lab