The Operation game features 13 pieces, including the Adam's apple, broken heart, wrenched ankle, butterflies in stomach, spare ribs, water on the knee, funny bone, writer's cramp, Charley horse, ankle bone connected to the knee bone, wish bone, bread basket and brain freeze. The purpose of "Operation" is to remove each of the these ailments from the body of Cavity Sam.
In addition to the ailments included in the body, other pieces of equipment needed to play the game include surgical tweezers, doctor cards and play money.
Players take turns selecting cards. Each card includes an image of one of the items included inside of Cavity Sam along with a monetary value. The player must then use the surgical tweezers to remove the corresponding item without touching the sides of the cavity with the tweezers. If the tweezers touch anything other than the ailment, Cavity Sam's nose will light up and buzz, and the player's turn ends.
If a player is able to successfully remove an item without touching anything else, he receives the amount of money listed on the card he chose at the start of his turn. The game proceeds until all ailments are removed. The player with the most money wins.