Alan Lee's late glancing header all but condemned Leeds to Coca-Cola Championship relegation and prompted a pitch invasion amid scenes of chaos at Elland Road.
Ipswich striker Lee flicked home Gary Roberts' 88th-minute cross to cancel out Richard Cresswell's first-half opener and sparked riotous scenes among furious fans for whom the reality of League One football next season proved too much to bear.
Referee Michael Jones had led the players from the field with several minutes of time added on still to play.
The 30-minute delay sparked chants of "You're the scum of Elland Road" from supporters who stayed in their seats.
Cresswell's first-half header appeared to have ensured Leeds' relegation battle would head down to the final day at Derby, but with closest rivals Hull winning at Cardiff, Ipswich striker Lee dealt Dennis Wise's side a brutal blow.
Stunned Leeds fans knew only a miracle on the last day will save them from the humiliating reality of life in the third tier of English football for the first time in their history.
Former Preston striker Cresswell stooped to head Wise's side into a priceless 12th-minute lead after David Healy's fierce shot had been parried by Ipswich goalkeeper Shane Supple.
But, with the clock ticking down, Lee nodded home to silence the 31,261-strong crowd and turn their last home game into a farce.
The players came back onto the field for one last frantic finale but, within a minute, referee Jones blew for full-time and promptly sprinted for the tunnel as Leeds' fate was virtually sealed.
Hayden Foxe replaced an unwell Matt Heath in the Leeds starting line-up, while on-loan Michael Gray returned from illness in place of Robbie Elliott.
Ipswich were unchanged from the side which drew 1-1 with Norwich last week, save for Lee swapping places with Jonathan Walters, who started on the bench.
For all the passion and noise from the terraces, it took Leeds 11 minutes to create an opening, Healy firing over the crossbar from Cresswell's knockdown.
But, 60 seconds later, the home side got the early breakthrough they craved.
Alan Thompson laid a golden chance on for Healy with an inch-perfect 40-yard pass after brilliantly turning his man on the halfway line.
Healy raced in on goal only to see his fierce angled shot parried by Supple, but the ball bounced into the path of Cresswell and the Leeds striker stooped to head home.
Ipswich responded but Francis Jeffers failed to take advantage of Owen Garvan's dangerous cross and former Leeds defender Dan Harding's 25-yard shot was tipped over the crossbar by Casper Ankergren.
Richardson did well to block Jeffers' goalbound effort and the former Everton and Arsenal predator had the Leeds goalkeeper at full stretch with a right-footed shot in the closing stages.
Lee was wayward with his header from Roberts' cross soon after the restart, with Leeds fans reminded one goal was unlikely to be enough.
News then filtered through that relegation rivals Hull had taken the lead at Cardiff and all of a sudden anxiety swept the terraces.
Healy brought a flying save out of Supple with a dipping volley, while at the other end Roberts went close with one of his own.
Lee's deft flick soon after played in substitute Walters, on for Jeffers, and his left-footed shot brought a fine reflex save from Ankergren.
Lewis hobbled from the field in the 77th minute to be replaced by Elliott before Cresswell flung himself at Blake's corner to power a header over the crossbar.
Wise sent on Ian Moore for a tiring Blake with eight minutes remaining as players from both sides grew weary in the sun.
Lee then caught Leeds' defence off guard for the first time in the game, finding space to glance home Roberts' ball into the penalty area.
Leeds poured forward with time fast running out and Foxe went close with an overhead kick before the game was delayed due to the pitch invasion.
The home fans quickly turned their attentions after the final whistle to defender Gary Kelly, who was honoured for 16 years' service at Elland Road.
But Kelly's tribute merely served to delay the harsh reality of Leeds' miserable campaign.
Teams:
Leeds Ankergren, Richardson, Foxe, Rui Marques,Gray (Kandol 88), Blake (Moore 82), Kishishev, Thompson,Lewis (Robbie Elliott 77), Healy, Cresswell.
Subs Not Used: Stack, Johnson.
Booked: Thompson, Foxe, Blake.
Goals: Cresswell 12.
Ipswich Supple, Wright, Bruce, Wilnis, Harding,Peters (Clarke 76), Garvan, Williams (O'Callaghan 63), Roberts,Jeffers (Walters 67), Lee.
Subs Not Used: Price, Richards.
Booked: Roberts, Garvan, Clarke.
Goals: Lee 88.
Att: 31,269
Ref: N. Jones. (England).