Spanish clubs Real Madrid and Barcelona maintain the top two slots in Deloitte's Football Money League, followed by Manchester United, Bayern Munich, Arsenal and Chelsea, the report said, based on revenue for the 2010/11 season.
"Continued growth of the top 20 clubs during 2010/11 emphasises the strength of football's top clubs, especially in these tough economic times," said Dan Jones, partner in the Sports Business Group at Deloitte.
"Whilst revenue growth has slowed from eight percent in 2009/10 to three percent in 2010/11, their large and loyal supporter bases, ability to drive strong broadcast audiences and continuing attraction to corporate partners has made them relatively resilient to the economic downturn," he added.
The top 20 generated 4.4 billion euros in revenue, more than a quarter of the total for European football as a whole.
Spain has been one of the European economies hardest hit by the euro crisis but Real Madrid and Barcelona are global brands that can be marketed to international viewers and sponsors.
"In much the same way as the Premier League is for England, they are very successful exports for the Spanish economy," Jones told Reuters.
"The challenge for Spain is that these two are so far ahead of the rest on and off the pitch."
Valencia, in 19th spot, were the only other club to make the top 20. The gulf between the rich and poor is wider in Spain than other countries because clubs sell TV rights individually rather than collectively.
BELT TIGHTENING
The top 20 - who make up the world's highest earning clubs - are drawn from the big five European leagues. Six are from England, five from Italy, four from Germany, three from Spain and two from France.
The value of the Champions League was underlined as German club Schalke 04 jumped six places to make the top 10 for the first time on the back of reaching the last four of the premier European club competition.
Revenue at Real Madrid was 479.5 million euros, against 450.7 million for Barcelona and 367 million for Manchester United, beaten by Barcelona in last season's Champions League final.
Deloitte warned that United were likely to fall more than a 100 million euros adrift of their Spanish rivals in the current year after an early exit from the Champions League.
Big spending English Premier League leaders Manchester City, backrolled by cash from Abu Dhabi, were 12th on the list while Qatari-backed Paris Saint-Germain, who top the French league, did not feature this time.
Many clubs continue to make big losses as they spend heavily on players to try to ensure success on the field.
However, new rules introduced by European football's governing body UEFA mean clubs must curb their losses or risk exclusion from major tournaments.
"Football clubs have been very successful over the past 20 years at generating more revenue but less good historically at cost control and that is what Financial Fair Play is
