Real Madrid, Barcelona and their rivals had already racked up debts totalling around 2.8 billion euro by June 2007 and slipped at least 664 million euro further into the red in the 12 months after that, said Jose Maria Gay, author of the study and a professor at the University of Barcelona.
"We are faced with a situation where the economic life blood of the clubs is seeping away," Gay said.
"Far from seeing signs of salvation, they are sinking ever further into the mire of enormous debt."
In an interview in January, Gay warned Spanish football faced financial collapse and urged the authorities to act to force clubs to stop living beyond their means.
Francisco Izco, president of Primera Liga side Osasuna, told Reuters this week a financial disaster could engulf football unless action is taken to prevent profligate clubs slipping deeper into the red.
Spain's professional football league (LFP) said it would respond to emailed questions about Gay's study later on Friday.
Gay based his latest analysis on the 2007/08 accounts of Real Madrid, Barcelona and most of their rivals but it does not include money owed to creditors by Real Valladolid, who have not made their accounts available since 2002/03, he said.
Levante, relegated at the end of last season, and Recreativo Huelva had not published figures after 2005/06 and the latest Almeria accounts available were from 2006/07.
The study showed champions Real Madrid had the largest debt in 2007/08 with 563 million euro, followed by city rivals Atletico with 511 million and Valencia with 502 million. Barcelona was 438 million in the red.
Valencia officials admitted last month they might have to sell top players to ease their financial woes and the club has been forced to delay wage payments and halt construction on a new stadium.
The Primera Liga is not the only league in Europe saddled with financial difficulties, with clubs in England owing around 3 billion pounds, according to FA chairman David Triesman last October.
A committee of British MPs said on Monday debt levels in English football were of great concern and takeovers should be blocked if they jeopardised financial stability.
