Clarke Carlisle's 43rd minute goal gave Leeds the lead as the defender struck the ball just inside the near post after his first attempt rebounded to him.
But Brighton gatecrashed the party and held on to a point despite the 88th minute dismissal of Charlie Oatway for kicking out at Leeds midfielder Simon Walton.
Bates was given a warm welcome by Leeds supporters as he took his seat in the directors box.
Brighton gave a debut to goalkeeper David Yelldell, on loan from Blackburn, while Adam Virgo and Mark McCammon also came in. Iceland midfielder Gylfi Einarsson made an impressive first start for Leeds who welcomed back Brian Deane, Walton and Aaron Lennon.
Einarsson almost scored within a minute, meeting Gary Kelly's cross and sending a bullet header too close to Yelldell.
Lennon's pace repeatedly troubled Brighton's defence and the youngster's trickery took him past Butters and Daniel Harding but Deane lost his footing in the goalmouth.
Brighton claimed they should have had a penalty when Paul Reid fell to David Healy's mild challenge, but referee Mike Thorpe disagreed.
Carlisle's goal was no more than Leeds deserved but Brighton began the second half much brighter in more ways than one.
Keeper Yelldell changed into a bright pink shirt, much to the amusement of the Leeds fans who teased him mercilessly. But he answered them by pulling off a superb save from Kelly.
Leeds keeper Neil Sullivan was also at his best to claw a swerving shot from substitute Gary Hart away from the top corner of the net.
Brighton deserved their equaliser but Leeds are making a habit of failing to hold on to a lead and they have now won only one of their last seven home matches.
Eirik Bakke made his comeback for Leeds after a long injury absence a few minutes from the end but still had time to pick up a booking.
MAN OF THE MATCH: Aaron Lennon (Leeds) The winger's pace had Brighton's defence dancing on hot coals.
But Brighton gatecrashed the party and held on to a point despite the 88th minute dismissal of Charlie Oatway for kicking out at Leeds midfielder Simon Walton.
Bates was given a warm welcome by Leeds supporters as he took his seat in the directors box.
Brighton gave a debut to goalkeeper David Yelldell, on loan from Blackburn, while Adam Virgo and Mark McCammon also came in. Iceland midfielder Gylfi Einarsson made an impressive first start for Leeds who welcomed back Brian Deane, Walton and Aaron Lennon.
Einarsson almost scored within a minute, meeting Gary Kelly's cross and sending a bullet header too close to Yelldell.
Lennon's pace repeatedly troubled Brighton's defence and the youngster's trickery took him past Butters and Daniel Harding but Deane lost his footing in the goalmouth.
Brighton claimed they should have had a penalty when Paul Reid fell to David Healy's mild challenge, but referee Mike Thorpe disagreed.
Carlisle's goal was no more than Leeds deserved but Brighton began the second half much brighter in more ways than one.
Keeper Yelldell changed into a bright pink shirt, much to the amusement of the Leeds fans who teased him mercilessly. But he answered them by pulling off a superb save from Kelly.
Leeds keeper Neil Sullivan was also at his best to claw a swerving shot from substitute Gary Hart away from the top corner of the net.
Brighton deserved their equaliser but Leeds are making a habit of failing to hold on to a lead and they have now won only one of their last seven home matches.
Eirik Bakke made his comeback for Leeds after a long injury absence a few minutes from the end but still had time to pick up a booking.
MAN OF THE MATCH: Aaron Lennon (Leeds) The winger's pace had Brighton's defence dancing on hot coals.