The clubs admitted failing to ensure that their players and/or officials conducted themselves in an orderly fashion and were respectively fined £10,000 and £5,000 by a Football Association disciplinary commission.
The hearing today considered charges issued after a 53rd-minute challenge by Blades' Keith Gillespie on Stephen Hunt sparked unsavoury clashes in the match at the Madejski Stadium.
Blades manager Neil Warnock and substitute Keith Gillespie were sent off while Reading coach Wally Downes was also dismissed for his part in the melee during Reading's 3-1 win.
Downes was today given a one-match touchline ban and £2,000 fine after admitting a charge of improper conduct.
The same charge against Reading academy manager Eamonn Dolan was withdrawn.
Reading assistant manager Kevin Dillon admits he is still annoyed at the way the Football Association have heaped punishment on the Premiership newcomers this month.
The Royals were told they must pay a £5,000 fine for failing to control their players following a touchline fracas in the 3-1 home win over Sheffield United on January 20, which involved coaching staff and back-up players from both sides.
Royals coach Wally Downes was fined £2,000 and handed a one-match touchline ban for sparking the brawl by angrily confronting Neil Warnock after the Blades boss had made a kicking gesture.
Downes and the club itself had earlier pleaded guilty to the charges but Dillon admitted he was still smarting at the three-match ban handed to striker Leroy Lita.
The England Under-21 international was punished when the FA used video evidence to examine an alleged headbutt on Charlton defender Talal El Karkouri.
But Dillon was convinced no offence had actually taken place and that he had lost respect for referee Graham Poll, who had missed the incident when it happened, and the governing body for not investigating whether the Charlton player had been guilty of gamesmanship.
He said: "His suspension was ridiculous and he's disappointed because he has had a great season. I can't even remember him being booked since he has been here.
"It's annoying when the referee compounds it by saying he would have sent him off had he seen it. There was another player on that pitch he should have sent off - and he did see it.
"I lost respect for him after what happened at Charlton."
Downes and manager Steve Coppell gave evidence at the FA's disciplinary hearing in Birmingham earlier today, with United ordered to pay a £10,000 fine.
An improper conduct against Reading academy manager Eamonn Dolan was withdrawn however.
Warnock had escaped charges after insisting his kicking gesture had been wrongly interpreted by Downes as an instruction to his players to hurt their opponents.
The bust-up occurred straight after referee Mark Halsey had shown a straight red card to Blades substitute Keith Gillespie, who had elbowed Reading midfielder Stephen Hunt just seconds after coming on the pitch.
Reading travel to Bolton on Saturday but will also be missing skipper Graeme Murty and winger Glen Little through injury. Striker Kevin Doyle has recovered from a hamstring problem and midfielder Steve Sidwell, who was dropped for last week's 1-0 victory over Fulham because he is likely to leave in the summer, is to travel north.
Reading will do so by air, having decided to charter an aircraft to fly them from Farnborough Airport to Manchester to avoid road congestion.
PA Sport