Add cream of mushroom soup, milk, salt, pepper, and Worcester sauce to the crock pot.
Stir until the soup and milk are mixed well. Then add the canned green beans and stir.
Once the green beans are coated with the soup mix you can put the lid on and cook on high for about 2 1/2 hours.
Carefully remove the crockpot insert from the metal heating element.
Sprinkle fried onions over the top of the green bean casserole and bake in the oven at 350 degrees for about 5 minutes or until the fried onions are starting to brown.
Remove and place back in crock pot base.