He was booked on suspicion of a felony, but officials would not provide further details.
A source with knowledge of the case described it as a domestic disturbance charge involving his girlfriend. He was being held on $50,000 bail.
Mariotti is a well-known sports commentator who can be seen on the ESPN show "Around the Horn." He also writes for a sports website called Fanhouse.com. Known for his outspoken views, he used to write a sports column for the Denver Post and the Chicago Sun-Times.
Details of the arrest were not immediately available.
[Updated at 9:30 a.m.: LAPD sources said Mariotti allegedly got into an argument with his girlfriend at a club in Santa Monica.
The argument continued at the couple's apartment in Venice, where some type of physical altercation occurred. Police were called to the apartment, and Mariotti was arrested.