The tax collectors released the statistics while emphasizing that they continue to improve their record on telephone calls and electronic services.
"We have augmented our enforcement efforts and brought in billions more to the Treasury, but not at the expense of services to taxpayers," said IRS Commissioner Mark Everson.
The IRS audited 1 in 63 wealthy individuals and families, those reporting $100,000 or more in earnings.
Overall, about 1 out of every 107 individuals and families faced an audit, more than last year when about 1 in 129 taxpayers were audited.
Audits of corporations and small businesses also climbed when compared with last year. About 20 percent of all corporations were audited during the fiscal year that ended on Sept. 30. The largest corporations, those with assets of $250 million or more, faced the highest audit rate at about 44 percent.
The number of small businesses that faced an audit also rose after a significant dip the year before. About 1 in 126 small businesses, those with assets less than $10 million, were audited this year.