To attain completion in The Lost and Damned, the player must accomplish all of the following:
- Complete 23 storyline missions (Clean and Serene to Get Lost).
- Complete 25 Gang War side missions.
- Complete 12 Bike Race side missions.
- Finish Importing/Exporting Bikes for Angus -10.
- Terminate 50 seagulls.
- Find two Random Characters.
- Complete Thomas Stubbs' jobs -5.
- Win a game of arm wrestling, pool, darts, and air hockey against anyone.
- Bring Terry Thorpe or Clay Simons to air hockey, darts, drinking, eating, pool, show, and strip club.