Kirby Corporation is the premier tank barge operator in the United States, transporting bulk liquid products throughout the Mississippi River System, on the Gulf Intracoastal Waterway, along all three U.S. Coasts, and in Alaska and Hawaii. Kirby's service includes the transporting of petrochemicals, black oil products, refined petroleum products and agricultural chemical products by tank barge. Kirby also owns and operates seven ocean-going barge and tug units transporting dry-bulk commodities in United States coastwise trade.

Through Kirby's diesel engine services segment, Kirby is the leading after-market service provider for medium-speed and high-speed diesel engines, reduction gears and ancillary products for marine and power generation applications. Kirby also serves as a distributor and service provider for high-speed diesel engines, transmissions, pumps and compression products, and manufactures and remanfactures oilfield service equipment, including presure pumping units, for the land-based pressure pumping and oilfield service markets.