According to Official Guinness Records,
The longest bartending marathon lasted 111 hours and was achieved by Ruth Brands (Belgium), at the Café Het Gildenhuis, Opglabbeek, Belgium, from 30 October to 4 Novemebr 2012. During the attempt, other staff members hosted events and ran fundraisers to raise money for a disabled children's charity. After setting the record, Ruth took a few hours to sleep before heading back to the bar for a celebratory party and to present the charity with a cheque for €12,111 (£10,277.50).
For a complete list of 2012 records, please visit 2012 Guinness Records in Belgium.