Lamar Odom was arrested for "driving under the influence of alcohol and/or drugs" early Friday morning ... TMZ has learned.

The bust occurred in the San Fernando Valley at 3:54 AM. Lamar -- who was driving a white Mercedes SUV -- was popped by the California Highway Patrol and taken to a nearby station where he was booked and is being held on $15000 bail.

He was pulled over on the 101 Freeway for going too slow -- 50 MPH. Cops say Odom had been driving in a "serpentine manner."

Lamar initially did not respond to cops and drove 3 exits before finally coming to a stop. Law enforcement sources tell TMZ he showed obvious signs of intoxication.