- "Objectives for your current case are listed in your notebook, and the log keeps a transcript of your investigation so far, accessible via the pause menu."
- ―In-game hint
Cases are the mission structures of L.A. Noire.
All cases begin in the same way. You're briefed by your Captain, you're treated to a short cutscene showing the crime taking place, then you and your partner head off to the crime scene to search for clues. Most of the cases feature interrogations and shootings. Depending on how many clues Phelps finds and how well he does during the interrogations, the course of the case might change; meaning each case can be solved multiple ways. At the end of each case, Phelps will receive a score of 1-5 stars, depending on how well he did in both investigation and interrogation. By receiving high scores at the end of a case, Phelps will move through the ranks of the LAPD faster.
Pre-order bonuses and DLC cases will not be counted as "Case Completed" in the game statistics except in the Remastered Edition, where they are counted.
- The Driver's Seat
- The Consul's Car (Exclusive to PS3 and PC; included on The Complete Edition)
- A Marriage Made in Heaven
- A Slip of the Tongue (Pre-order bonus and DLC; included on The Complete Edition)
- The Fallen Idol
- The Red Lipstick Murder
- The Golden Butterfly
- The Silk Stocking Murder
- The White Shoe Slaying
- The Studio Secretary Murder
- The Quarter Moon Murders
- The Black Caesar
- Reefer Madness (DLC across all platforms; included on The Complete Edition)
- The Set Up
- The Naked City (Pre-order bonus and DLC; included on The Complete Edition)
- Manifest Destiny
- The Gas Man
- A Walk in Elysian Fields
- House of Sticks
- A Polite Invitation
- Nicholson Electroplating (DLC across all platforms; included on The Complete Edition)
- A Different Kind of War