The existence of a sex pheromone of Bradysia odoriphaga Yang and Zhang was investigated prior to the possible development of a semiochemical-based monitoring system or tools for controlling this pest. In laboratory bioassays, live virgin females stimulated 91% of males to attempt to mate. Methylene dichloride washes of whole bodies and excised ovipositors of females attracted males in olfactometer assays. These results indicate the presence of a female sex pheromone in B. odoriphaga, with the ovipositor as its possible source.