David Prutton headed home from 6 yards in the 17th minute, after Leeds had dominated play from the start, 1-0.
Hopes of more goals in the first half began to fade as United took their foot off the pedal and the Valiants increased their share of possession.
After the restart Leeds got a grip of the game again and a right foot shot, from 12 yards, in the 54th minute, gave Jermaine Beckford his 11th league goal of the season so far, 2-0.
An injury to Beckford in the 64th minute brought on Tore Andre Flo for what is said to be his first pain free game for 10 months; Jonathan Howson came on for Radistin Kishishev on 73 minutes, Ian Westlake was replaced by Alan Thompson in the 80th minute.
On 82 minutes Flo volleyed a right foot shot, from 20 yards, straight into the back of the net, 3-0.
This was a much improved performance by United, who have clearly benefited from the 10 day break.
Attendance - 20,301
Leeds United 3 Port Vale 0