The company's Football Money League, published for the 16th time on Thursday, features Spanish champion Madrid retaining its hold on first place ahead of perennial rival Barcelona.
In an unchanged top six, Manchester United remains third, Bayern Munich fourth, European champion Chelsea fifth and Arsenal sixth, but English champion Manchester City soars five places to seventh.
AC Milan falls one place to eighth, with Liverpool remaining ninth and Italian champion Juventus rising three places to complete the top 10.
Madrid's revenue rose by seven per cent to 512.6 million euros ($655.53 million) in the 2011-2012 season.
It enabled the nine-time European champion to hold on to top spot in the ranking for an eighth successive year, matching United's record from 1996-1997 to 2003-2004.
"It is an impressive achievement for Real Madrid to have surpassed 500 million euros in revenue in a single year," said Dan Jones from Deloitte's Sports Business Group.
"Real have led the way in the phenomenal rate of revenue growth achieved by the game's top clubs, with the double-digit (10 per cent) increase by the top 20 clubs representing continued strong performance in these tough economic times.
"The combined revenues of the top 20 clubs have quadrupled since we began our analysis in 1996-97."
Madrid triumphed in the Spanish Liga in 2011-2012, ending three years of dominance by arch-rival Barcelona, but lost out in the UEFA Champions League after being beaten by Bayern in the semi-finals.
Overall, the combined revenue of the world's 20 highest earning football clubs grew by 10 per cent on the previous year to reach 4.8 billion euros ($6.14 billion).
City's climb of five places was matched by German champion Borussia Dortmund, which rose to 11th, and Italian side Napoli (15th).
The only new entry in the list was English side Newcastle United, which moved into the top 20 at the expense of Spanish club Valencia after a surprise fifth-place finish in the Premier League last season.
The English top flight remains the most well-represented league in the ranking, with seven of the 20 clubs hailing from the Premier League.