Thin-layer chromatography of the cuticular lipids of horse flies from Oklahoma revealed that hydrocarbon was the major lipid class present. The hydrocarbon fraction was composed of n-alkanes and methyl branched alkanes with only a small amount of alkenes present. Gas chromatography of the isolated cuticular hydrocarbons from a single species, Tabanus abactor Philip, showed no major differences in the profiles between individuals or between the sexes. Analysis of extracts of fresh, frozen, and pinned specimens yielded nearly identical hydrocarbon profiles. Profiles of several species were examined and found to be unique for each. Three species with similar morphological characteristics and similar geographical ranges. Tabanus abdominalis F., T. limbatinevris Macquart, and T. sulcifrons Macquart, were differentiated easily by comparison of the hydrocarbon profiles.