Females of the horse-chestnut leafminer Cameraria ohridella Deschka & Dimić (Lepidoptera: Gracillariidae) produce a highly attractive sex pheromone in the early photophase. The pheromone, luring conspecific males into Delta traps baited with females, is produced in the female abdominal tip (ca 10-50 pg per calling female) and the active components can be extracted with hexane. Both dissected tips and their hexane extracts show high attractiveness for C. ohridella males in a wind tunnel behavioural bioassay. According to electrophysiologic recordings the male antennae are notably sensitive to both dissected female abdomens and extracts from them. The strong attractiveness of the pheromone may be useful in control of this pest.