The loss, which the La Liga champions said was the first in seven years, highlights the financial state of many Spanish clubs, with even wealthy Barca - second behind Real Madrid in the latest ranking of the richest clubs by revenue by accounting firm Deloitte - slipping into the red.
The new Barca audit, conducted by Deloitte, showed operating income of 408.9 million euros and costs of 477.9 million compared with previous figures published under former president Joan Laporta of 445.5 million income and 429 million costs, the club said on their website on Tuesday.
Javier Faus, a Barca vice president, told a news conference the club's net debt had swelled to 442 million euros from 329 million at the end of the 2008/09 season.
"There is a structural problem," Faus said. "The sporting excellence of the past few years has not been reflected in excellence in economic management."
A deep recession, the collapse of the real estate market and surging wage and transfer costs have combined to push many of Spain's top-flight clubs deeper into the red and forced some, such as Real Mallorca, into administration.
After Laporta's exit at the end of June, Barca admitted cashflow difficulties and were forced to seek a 150-million-euro bank loan to address "liquidity problems."
One of the reasons for the poorer clubs' woes is the dominance Real and Barca command over revenue from television rights.
Unlike in rival European leagues, television deals, a key revenue stream, are negotiated individually and Real and Barca rake in about half of the 600-million-euro pot.
A study by University of Barcelona professor Jose Maria Gay published in May showed the 20 clubs in La Liga had combined debt of 3.526 billion euros in 2008/09, up from 3.49 billion the previous season.
