O.D. Green camouflage appears in Call of Duty: Modern Warfare Remastered, unlocked after achieving 75 kills on a specific weapon without any attachments equipped for all primary weapons except the XM-LAR, which requires 50 kills without any attachments, 25 kills without attachments on all pistols, or for the case of the Desert Eagle and MP44, 25 kills and 75 kills while crouching respectively.
This camouflage appears as a drab, olive color scheme.
O.D. Green camouflage with an example of the challenge required to unlock it.