Chester Turner, 44, made that plea in a downtown L.A. courtroom Thursday.
Turner was sent to death row four years ago for murdering 10 women in L.A. County between 1987 and 1998.
The new charges were filed earlier this year for the murders of four other women during the same time period in an area south of downtown called the Figueroa Corridor.
Turner is due back in court July 12 for a hearing to determine whether there is enough evidence for him to stand trial.
