Country has become the only category to report an increase in sales on the previous year.
Artists such as Shania Twain, the Dixie Chicks and Alan Jackson helped country sales to increase by 12%.
Along with hip-hop, country accounted for three-fifths of number one albums in the US, according to the New York Times newspaper.
The success of the two genres was at odds with the overall picture - a 9% slump in CD sales.
Among the year's biggest acts were country pop trio the Dixie Chicks, whose album Home was the fourth best-selling CD of the year with 3.7 million sales.
Other big country sellers included Alan Jackson's album Drive, Up by Shania Twain, and the soundtrack to the film O Brother, Where Art Thou?
Twain's album, which had topped the charts since its release in late November, was finally toppled on Thursday by the 8 Mile film soundtrack, featuring Eminem.
Eminem has stood out as by far the single most successful artist in the US during 2002.
His album The Eminem Show was the biggest seller of the year, with 7.6 million sales - while 8 Mile came fifth with nearly 3.5 million sales.
The 8 Mile film in which he makes his acting debut has grossed more than $114m (£71m).
Nielsen SoundScan, which compiles the US music charts, revealed that across the industry as a whole, album sales fell 8.7% to about 650 million.
It was the second consecutive annual drop, and has been blamed on the slow state of the US economy and internet music piracy.
Universal ended 2002 as the US's biggest music company, followed by Warner and Sony.