The Underboss is the second most important position in a Mafia crime family directly beneath the don himself. The underboss is often a relative of the current don and is appointed by the boss himself. The underboss is in charge of all of the capos and is usually first in line to become acting boss if the boss is imprisoned or dies. There are normally no more than two underbosses in a family, if there's more than one at all.
- Mafia: The City of Lost Heaven
- Mafia II
- Rocco (Falcone Crime Family, Unknown - 1950)
- Eddie Scarpa (Falcone Crime Family, 1950 - 1951)
- Duke Tussle (Bombers, Unknown - 1950s) (The Betrayal of Jimmy)
- Tiny Gravina (Gravina Crime Family, Unknown - 1950s) (Jimmy's Vendetta)
- Mafia III