Michael Ricketts scored his first goal for 11 months as Leeds eased into the second round of the Carling Cup.
Ricketts muscled his way behind the Oldham defence before firing across Chris Day and into the far corner.
Soon after it was 2-0 when David Healy produced a delightful backheel and Frazer Richardson netted from 12 yards.
Andy Liddell's free-kick hit the side-netting and defender Guy Branston saw a header cleared off the line before Ricketts opened the scoring.
Leeds: Sullivan, Rui Marques, Gregan, Kilgallon, Crainey, Richardson, Einarsson, Douglas, Pugh, Ricketts, Healy (Blake 81).
Subs Not Used: Wright, Bennett, Moore, Harding.
Goals: Ricketts 20, Richardson 24.
Oldham: Day, Scott, Branston, Owen, Forbes, Wellens, Hughes (Bonner 73), Tierney, Facey, Warne (Edwards 73), Liddell.
Subs Not Used: Stam, Eyres, Smith.
Ref: K Wright (Cambridgeshire).