The 2003 Grand National (officially known as the Martell Grand National for sponsorship reasons) was the 156th official renewal of the world-famous Grand National steeplechase that took place at Aintree at 3:45pm BST, on 5 April 2003.
 The ten-year-old 16/1 shot Monty's Pass, ridden by Barry Geraghty and trained by Jimmy Mangan in Cork, Ireland, won the race by 12 lengths from the 2001 Welsh National winner Supreme Glory (40/1) in a time of 9 minutes 21.7 seconds.
 The field was limited to a maximum of 40 competitors, and 14 completed the 4 mile 4 furlong course. Bramblehill Duke was a late replacement for the withdrawn Kingsmark a day before the race.
 (st-lb)
 Shotgun Willy became the favourite for the race after winning the Red Square Vodka Gold Cup at Haydock on 1 March and remained the most popular entrant with the public, going off as the 7/1 clear favourite, ridden by Ruby Walsh who had previously won the race in 2000. Shotgun Willy was always towards the rear of the field and began to lose touch with the leaders early on the second circuit, pulling up after making a mistake at the 21st fence.
 Youllneverwalkalone won the Leopardstown Chase in January and then the William Hill Handicap Chase at Cheltenham in March and was sent off as the 8/1 joint-second favourite in partnership with rider Conor O'Dwyer. The horse was naturally popular with punters on the Liverpool course due to links with Liverpool Football Club whose anthem is the song of the same name, however the horse was at the back of the field when he suffered a leg injury at the 11th fence and was instantly pulled up. He was found to have broken a leg and, although he recovered, was never raced again.
 Iris Bleu had fallen in the 2002 National but had won the Thomas Pink Handicap Chase at Cheltenham in December and the Agfa Diamond Chase at Sandown in January to be backed to 8/1 on race day. Ridden by champion jockey Tony McCoy, Iris Bleu made a series of mistakes and was pulled up lame before taking the water jump at the end of the first circuit.
 Ad Hoc had been travelling well when brought down in the 2002 race, and was partnered by 1999 winning jockey Paul Carberry; the pair went off at a price of 9/1 and almost fell at the first fence. Having recovered, they were making progress when Carberry was unseated at the 19th.
 Chives had run prominently in several major races, including finishing second in the 2002 Welsh National and seventh in the Cheltenham Gold Cup and was sent off at 10/1 in company with 1998 winning rider Richard Guest but also disappointed with mistakes before suffering injury at the 11th fence where he was pulled up.
 At 16/1, Monty's Pass was considered among the good each-way chances for the race and had been backed heavily on race day from 40/1 the day before after being tipped by several leading tipsters. Among those who predicted his victory were John Francome in The Sun, Eddie Fremantle in The Observer, Marten Julian in The Sunday Telegraph and Thunderer in The Times while Pricewise in the Racing Post tipped the horse to win two months before the race.
 
Big outsider Tremallt led the field over Melling Road and towards the first fence, where The Bunny Boiler unseated its rider and was the only casualty. The next fence saw Bramblehill Duke fall when chasing the leaders. At the third fence which was the first open ditch, Wonder Weasel was the only faller in mid division . Tremallt continued to lead the race over the fences before Becher's Brook. At Becher's Brook, Fadalko overjumped the fence and unseated its rider. Meanwhile, last year's winner Bindaree blundered and was on his nose after jumping the fence. The field all managed to jump the Foinavon fence well and ran on towards the Canal Turn. At this fence, Polar Champ blundered and unseated its rider when behind. Montifault joined Tremallt at the front of the race while jumping Valentine's Brook. 10/1 shot Chives blundered at the eleventh fence which was another open ditch and was pulled up before the next after breaking a blood vessel. At the next fence, another fancied horse Youllneverwalkalone jumped it slow and was immediately pulled up lame. Leading up to The Chair, Gunner Welburn had become the race leader. However the horse hesitated before jumping the fence and nearly unseated its rider. Katarino unseated its rider Mick Fitzgerald after making a mistake at The Chair and Ballinclay King was pulled up at the rear of the field. The next fence which was the Water Jump saw Iris Bleu pulled up. Thirty horses were still left standing when they continued the race onto the second circuit. All horses jumped the next two fences safely, at the 19th fence (open ditch) Monty's Pass and Torduff Express joined Gunner Welburn in the lead. Maximize fell, Ad Hoc and Goguenard both blundered and unseated their riders. You're Agoodun and Robbo were both hampered and unseated their riders also. Good Shuil was pulled up after tailing off at the same fence. At Beecher's Brook second time round Killusty fell in mid division and Burlu when behind for most of the race, while at the rear of the field the favourite Shotgun Willy pulled up as was Empereur River.  Gingembre was pulled up well behind at the Canal Turn. At the next fence which was Valentine's Brook, Mantle's Prince made a mistake and unseated its rider and Red Ark was pulled up at the fence towards the rear of the field. At the 27th fence final open ditch of the race Torduff Express had weakened, blundered and unseated its rider as did Red Striker. Cregg House refused the fence after tailing off . A group of Gunner Welburn, Monty's Pass, Amberleigh House and Montifault pulled away from Supreme Glory and the rest of the field as they crossed Melling Road to jump the final two fences. Monty's Pass jumped the last two fences ahead of Amberleigh House and a weakening Gunner Welburn. On the run-in Supreme Glory seemed to be staying on well after overtaking Amberleigh House just before the elbow. Although Monty's Pass stayed on well to go clear and win the race by 12 lengths ahead of Supreme Glory in 2nd and Amberleigh House in 3rd. Gunner Welburn and Montifault finished 4th and 5th after making a lot of the running in the race. Bindaree stayed on well to finish 6th after spending most of the race towards the rear. Next to finish was Carberry Cross, Blowing Wind, Tremallt, Behrajan, Djeddah, Majed, Royal Predica and last to complete was Southern Star. 14 horses completed the race.
 Winner Monty's Pass claimed a prize of £348,000, with £132,000 awarded to Supreme Glory in second, £66,000 for Amberleigh House in third, £30,000 for Gunner Welburn in fourth, £15,000 for Montifault in fifth, and £9,000 for sixth-placed Bindaree.
 Some bookmakers offered stakes refunds to customers who backed the first fence faller The Bunny Boiler. William Hill reported that they had to pay out £400,000 on two winning bets alone, claiming it was their worst hit in Grand National history.
 In post-race interviews, winning trainer Jimmy Mangan said: "It's a thing you dream about. To have a winner is unreal." Jockey Barry Geraghty said of his ride: "He was like a cat. He jumped unbelievable."
 Both the vets and the doctors were busy after the race. Goguenard was euthanised when he was caught in a melee at the 19th fence. Youllneverwalkalone was taken to the Liverpool horse hospital when it was found he had broken a leg in running. The injury was repaired and the horse retired from racing. Iris Bleu pulled up lame, while Ballinclay King and Chives both broke blood vessels. All three horses made a full recovery. Four riders also required hospital treatment after the race. Gerry Supple suffered a broken leg, Alan Dempsey a broken wrist, Brian Crowley a broken collarbone and Timmy Murphy suffered concussion and a broken nose.
 The BBC retained the rights to broadcast the race on television and radio for the 44th consecutive year, in accordance with the Ofcom Code on Sports and Other Listed and Designated Events. The race was broadcast as a Grand National special edition of the regular Saturday television show Grandstand, and involved three hours of build-up to the race through features on the principal contestants and the history of the race. The race itself was broadcast live and was followed by a detailed re-run using slow motion footage and additional camera angles not used in the original broadcast.
 The show was presented by Clare Balding and Sue Barker while the commentary team was John Hanmer, Tony O'Hehir and Jim McGrath who called the winner home for the sixth year. It was the last time that Hanmer commentated on a Grand National, having covered the portion from the Melling Road to the fourth and from the tenth to the Anchor Bridge crossing for thirty-two years.
 In total 52 cameras were used to cover the event including three cameras placed inside jockeys' caps and four inside selected fences. Former Grand National riders Richard Pitman and Peter Scudamore also talked the viewers through an in-depth re-run of the race in slow motion.
 In a new innovation the BBC introduced interactive services, which enabled UK viewers to access features such as a statistical predictor, archive footage of previous Nationals and a split-screen view of the race itself to enable viewers to watch the race from the air as well as the normal tracking cameras.
 Racing UK broadcast the race live into bookmakers' outlets throughout the country, though its camera angles were limited in comparison to the close-up coverage provided to BBC viewers.
 BBC Radio also broadcast commentary of the race live for the 71st time on its Sport on Five programme, presented by Mark Pougatch and with Lee McKenzie calling the runners home. Also among the commentary team was Ian Bartlett, who was to replace John Hanmer in the television commentary team the next year.
 Two-time winner Carl Llewellyn was the most experienced rider in the race, weighing out for a Grand National for the thirteenth time, while eleven riders made their debut. Leighton Aspell fared best of those, finishing second, with Graham Lee finishing third while Liam Cooper, Jamie Moore and Dominic Elsworth also completed the course. John Cullen's debut ended at the first fence while Daniel Howard, Davy Russell, Alan Dempsey, Patrick Paihes and Larry McGrath also failed to get round.