Preheat your oven to 375°F (190°C). Grease an 8 x 8 casserole dish.
In a large bowl, combine the cooked egg noodles, cream of mushroom soup, and drained tuna. Mix well until all ingredients are evenly combined.
Transfer the mixture into a greased casserole dish, spreading it out evenly.
Top the casserole with breadcrumbs.
Place the casserole dish in the preheated oven and bake for about 25-30 minutes, or until the casserole is hot and bubbly.
Once done, remove from the oven and let it cool for a few minutes before serving.