Albion stretched their unbeaten League run to six games with a smash and grab point against the big spending Welshmen.
Bobby Zamora capitalised on a dreadful blunder by Cardiff rightback Rhys Weston to give the Seagulls a 36th minute lead.
Micky Adams' men looked like holding on until Paul Brayson levelled ten minutes from time.
Albion were under the cosh throughout the first half before a crowd of 12,022 at sunny Ninian Park.
Michel Kuipers was in commanding form again, saving downward headers from corners by Spencer Prior and £1.8 million striker Peter Thorne.
Former Cardiff target Zamora stunned the home fans with his eighth goal of the season and third in as many away matches.
Weston inexplicably misplaced a harmless cross from Danny Cullip back towards his own goal.
Keeper Neil Alexander rushed back to claw the ball away as it was about to cross the line, but Zamora followed up to score from close range.
The Seagulls, on the back foot for most of the match, showed tremendous spirit and resilience to keep Cardiff at bay.
Cullip was awesome at the heart of the defence once more alongside the similarly outstanding Simon Morgan.
Cardiff were beginning to look resigned to a second successive home defeat when Brayson pounced after Jason Bowen's header from a cross by fellow substitute Andy Legg struck a post.
The result put Micky Adams on course for the manager of the month award for September following four wins and two draws, although Oldham's home victory over Notts County has knocked the Seagulls off the top of the table on goal difference.
Brayson's late equaliser also relieves the pressure on Adams' close friend and former assistant Alan Cork at Cardiff after three defeats out of four.
Albion face Brentford, one of Adams' former clubs, at Withdean next on Friday (7.45pm) to avoid a clash with England's World Cup qualifier against Greece.
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