Los Angeles city attorney spokesman Frank Mateljan says the Grammy-winning singer entered the plea Monday and was sentenced to three years of informal probation.
Police say the 37-year-old Evans was arrested after being stopped at a DUI checkpoint in Marina del Rey.
She is the widow of rapper Christopher Wallace, also known as the Notorious B.I.G. Evans won a Grammy in 1998 for the song "I'll Be Missing You."
It was not immediately clear whether she was represented by an attorney. A phone message left with her agent, Marc Gerald, was not immediately returned.
Evans' plea was first reported by celebrity website TMZ.