In Drosophila melanogaster, the main cuticular hydrocarbons (HCs) are some of the pheromones involved in mate discrimination. These are sexually dimorphic in both their occurrence and their effects. The production of predominant HCs has been measured in male and female progeny of 220 PGa14 lines mated with the feminising UAS-transformer transgenic strain. In 45 lines, XY flies were substantially or totally feminised for their HCs. Surprisingly, XX flies of 14 strains were partially masculinised. Several of the PGa14 enhancer-trap variants screened here seem to interact with sex determination mechanisms involved in the control of sexually dimorphic characters. We also found a good relationship between the degree of HC transformation and GAL4 expression in oenocytes. The fat body was also involved in the switch of sexually dimorphic cuticular hydrocarbons but its effect was different between the sexes.