Yes they are, according to this article pposted on their website.
Korean Air Cargo - World’s Number One!
SEOUL, Korea (July 1, 2005) - Korean Air’s cargo operation has been ranked the world’s largest commercial airline cargo operation by the International Air Transport Association (IATA).
This is the first time the Korean flag carrier has achieved the world’s number one position in terms of international scheduled freight tonne-kilometres.
”This achievement is the result of our aggressive strategy to constantly enter new markets, build up our infrastructure and create strategic partnerships to meet our customer’s growing needs,” said Yang Ho Cho, Chairman and CEO of Korean Air.” During 2004, Korean Air recorded 8.164 billion FTK (Freight Tonne-Kilometres) ahead of the long-time number one carrier since 1986, Lufthansa Cargo. Korean Air has been ranked among the top three freight carriers since 1993, and has consistently placed among the top five commercial airline cargo carriers in FTKs since 1991.
Three other Asian airlines filled out the top five cargo carriers. Singapore Airlines ranked third, Cathay Pacific ranked fourth, and China Airlines ranked fifth.
In March of last year, Korean Air announced that its goal was to be the largest commercial airline cargo carrier by 2007. Korean Air has been carrying cargo since its establishment in 1969, and has been able to build up its operations as the Korean economy grew and expanded over the past several decades. The airline is the leading transporter of hi-tech items and other specialized goods, and its accumulated experience since establishment has enabled it to offer high quality services to meet the needs of its customers. The Hanjin Group, of which Korean Air is the largest subsidiary, is one of the world’s leading transportation conglomerates specializing in air, sea and ground transportation.
Korean Air's cargo operation spans the world carrying cargo to 39 destinations in 25 countries worldwide. Korean Air has a fleet of 113 aircraft including 18 freighters. For more information about Korean Air and its cargo operation, log onto http://cargo.koreanair.com.