Lutzomyia pessoai has been named as a probable vector of Leishmania braziliensis in southern Brazil. Males of this species have recently been shown to have pheromone-disseminating structures on their abdomen. Chemical analysis of extracts from the glands associated with these structures has revealed the presence of a possible sex pheromone. Although this compound has been partially characterized as a monocyclic diterpene with the same molecular weight as the Lu. longipalpis diterpene sex pheromone, mass spectral evidence indicates that it is a different compound. This, the first evidence for a possible sex pheromone in any phlebotomine species other than Lu. longipalpis, indicates that such semiochemicals may be widely distributed in this group.