The accounts, for the year to June 2009, show United's debts passing £700m for the first time.
More than £68m was paid in interest alone, the accounts show.
Despite the debts, the club turned a profit of £6.4m for the year - a marked improvement on the £47m loss reported at the end of the 2007/08 season.
The accounts also show that player sales brought in a profit of £80.7m - the price paid by Real Madrid for Cristiano Ronaldo in the summer.
The increased size of Manchester United's debts, and the amount of money being used to pay interest on them, are likely to concern fans.
Earlier this year, the Glazer family, which has controlled Manchester United since 2005, announced plans for a £500m bond issue designed to reduce debt repayments.
Source: BBC Sport
Source: BBC Sport