The mycolic acids and fatty acids of mycolic acid- containing bacteria in various types of fluids were analyzed using capillary gas chromatography and mass spectrometry. As model strains, Brevibacterium and Coryebacterium species, which have corynomycolic acids ill the range of $C_{32}C_{36}$ in the whole cell, were investigated. Optimized solvents extraction procedures for the mycolic acids and fatty acids from the culture fluids were: chloroform/methanol (1:2, v/v) as the first extraction solvents fur 4 h; and chlorofunuwater (1:1, v/v) as the second extraction solvents far 1 h. These conditions gave above 95% recovery yields fur mycolic acids from the culture fluids. The mycolic acid profile for the whole cells and the culture fluids were similar fur all the media tested. Thus, the procedure described here could be applied for the identification of mycolic acid-containing bacteria in fermentation broth or liquid from of foods.