The 2004 Football Second Division play-off final was an association football match which was played on 30 May 2004 at the Millennium Stadium, Cardiff, between Brighton & Hove Albion and Bristol City to determine the third and final team to gain promotion from the Football League Second Division to the Football League Championship. The top two teams of the 2003–04 Second Division season, Plymouth Argyle and Queens Park Rangers, gained automatic promotion to the Championship, while the teams placed from third to sixth place in the table took part in play-off semi-finals; the winners of these semi-finals competed for the final place for the 2004–05 season in the Championship. Brighton and Bristol defeated Swindon Town and Hartlepool United, respectively, in the semi-finals.

The final kicked off around 3 p.m. in front of a crowd of 65,167 and was refereed by Richard Beeby. The first half ended scoreless: Brian Tinnion's free kick was kept out by Brighton's goalkeeper Ben Roberts, and after Tommy Doherty fouled Nathan Jones in the 43rd minute, Leon Knight's curling free kick from 20 yards (18 metres) struck the Bristol City crossbar. Neither side made any changes to their personnel during the interval. On 84 minutes, Chris Iwelumo was brought down by Danny Coles in the Bristol City penalty area. The referee awarded a penalty which Knight struck past Steve Phillips in the Bristol City goal. Bristol City pressured late but could not score, and the match ended 1–0 with Brighton being promoted to the newly renamed Football League Championship (formerly Football League First Division).

Brighton ended the next season in twentieth place in the First Division, two places and one point above the relegation zone. Bristol City manager Danny Wilson left the club the week after the final. In their following season, Bristol City finished in seventh position in the Second Division and missed out on the play-offs by one place and one point.

Bristol City finished the regular 2003–04 season in third place in Football League Second Division, the third tier of the English football league system, one place ahead of Brighton & Hove Albion. Both therefore missed out on the two automatic places for promotion to the Football League Championship and instead took part in the play-offs to determine the third promoted team. Bristol City finished one point behind Queens Park Rangers (who were promoted in second place) and eight behind league winners Plymouth Argyle.

Brighton's opponents for their play-off semi-final were Swindon Town with the first match of the two-legged tie taking place at the County Ground in Swindon on 16 May 2004. In the 35th minute, a shot from Swindon's Sammy Igoe hit the Brighton goalpost, and midway through the second half, Tommy Mooney's strike hit the underside of Brighton's crossbar. With 18 minutes remaining, Richard Carpenter's deflected shot beat Rhys Evans in the Swindon goal to secure a 1–0 victory for the visitors. The second leg was played four days later at the Withdean Stadium in Brighton. After a goalless first half, Sam Parkin put Swindon ahead with a close-range shot in the 81st minute. With the aggregate score level 1–1 at full time, the game went into extra time, and midway through the first period, Rory Fallon put Swindon ahead with a low shot under Brighton's goalkeeper Ben Roberts. A diving header from Adam Virgo in the last moments of extra time made it 2–2 on aggregate and sent the match to a penalty shootout. Mooney missed his penalty and Andy Gurney's spot kick hit the post, and with all the other shots being converted, allowed Brighton to progress to the final with a 4–3 win on penalties.

In the second semi-final, Bristol City faced Hartlepool United; the first leg took place at Victoria Park in Hartlepool on 15 May 2004. The visitors took the lead after four minutes when Tony Rougier headed in Lee Peacock's cross. Joel Porter equalised for Hartlepool in the 74th minute to secure a 1–1 draw. The second leg was held three days at Ashton Gate in Bristol. Five minutes before half-time, Adam Boyd hit Bristol City's goalpost and the half ended goalless. Midway through the second half, Hartlepool's Antony Sweeney scored with a header from an Eifion Williams cross. With two minutes remaining, Marc Goodfellow levelled the match with a header before Christian Roberts made it 2–1 to Bristol City in the last minute, sending his side to the final with a 3–2 aggregate victory.

Brighton had participated in one play-off final prior to 2004, when they lost 3–1 to Notts County in the 1991 Football League play-offs. This was Bristol City's fourth involvement in the play-offs and their second final; they had lost in the semi-finals in 1997 and 2003, and in the 1988 Football League Third Division play-off final 4–0 by Walsall after a replay. Brighton had been relegated from the First Division the previous season so were aiming for an immediate return, while Bristol City had played in the Second Division since suffering relegation from the First Division in the 1998–99 season. In the matches between the clubs during the regular season, Bristol City won the game at the Withdean 4–1 in November 2003, while the game the following April at Ashton Gate ended in a goalless draw. Brighton's top scorer during the regular season was Leon Knight with 25 goals, all in the league. For Bristol City, Peacock led the scoring with 16 goals (14 in the league and 2 in the League Cup).

Brighton manager Mark McGhee expressed hope that his club's exposure at a major final would bring publicity to their aim to build a new ground, saying he believed "the final would be a fantastic platform to demonstrate how badly we need a bigger stadium". McGhee had lost in three previous play-off semi-finals and was "happy for City to be favourites" to win this final. He had taken the job as Brighton manager in October 2003, having left Millwall two weeks earlier "by mutual consent". His counterpart, Danny Wilson, had been in charge at Bristol City since 2000, and had led the team to victory in the 2003 Football League Trophy Final at the Millennium Stadium. He said: "There's so much at stake, it'll be very tense. What I will guarantee is that we'll give everything ... All that work we did as far back as last July now hinges on 90 minutes or even one penalty kick."