The most pull ups in 24 hours was 4,020 by Stephen Hyland (UK) at his personal gym in Stoneleigh, UK, on 23 July 2011.
Hyland needed only 12 hours to reach 4,020 pull ups, a total which qualified him for the 24-hour record. He varied between sets of 7 pull-up repetition, six, five, and four as the time progressed.
Please note: Comments below may relate to previous holders of this record.