Manchester United have been fined 1.652 million pounds ($2.65 million) as one of 10 companies found by Britain's competition watchdog to have fixed the prices of Umbro replica football kits.
The Football Association was also among the companies hit and was fined 198,000 pounds, the Office of Fair Trading (OFT) said on Friday.
The other firms were mainly sportswear retailers, with JJB Sports handed the biggest fine of 8.373 million pounds followed by the kit manufacturers Umbro (6.641 million) out of a total 18.6 million in fines.
"The fines imposed reflect the seriousness of the price fixing in this case," said OFT chairman John Vickers.
"Since we launched our investigation the prices of replica football shirts have fallen and consumers can now shop around and get a better price," he said.
United said they were disappointed with the OFT's action.
"Manchester United has cooperated fully with the OFT throughout its investigation and has vigorously and consistently defended its position in relation to the allegations of price fixing," the club said in a statement.
"Manchester United maintains it has not participated in price fixing in the market for replica kit."
The club said it would be considering an appeal and would make a further announcement in due course.
The price fixing concerned the selling of short-sleeved adult and junior shirts for England and Manchester United, as well as Chelsea, Celtic and Nottingham Forest, and took place during key periods such as the European championship in 2000.
In 2000 and 2001 most retailers charged just under 40 pounds for adult short-sleeved shirts and just under 30 pounds for the junior variety.
During a recent survey the OFT found the price of shirts now ranged from 24 to 40 pounds for adults and 18 to 30 pounds for juniors.
The FA said: "The FA has sought to co-operate at all times with the OFT and has made it clear that it only entered into a very limited arrangement in order to increase the availability of England kit, which had previously not been available over the internet or all year round.
"The FA takes its duties to football and the footballing public very seriously. That was why it took steps to widen the availability of the England replica kit -- a kit that is immensely popular with fans."
The FA said it had taken steps to ensure its future shirt sales operations would fully comply with competition law.