The behavioural responses of reproductive and non-reproductive female round gobies Neogobilis inetanostomus to water conditioned by reproductive and non-reproductive males and females were tested. The behavioural responses of reproductive female round gobies exposed to odour of reproductive males included increased time spent near the Source of the odour, elevated swimming velocities and directed movement to and around the odour source when compared with their responses to control water. These results suggested that pheromones released from reproductive males may induce spawning behaviour in reproductive females. Non-reproductive females exposed to reproductive female odour spent significantly more time near the odour source of reproductive females compared with control water. Non-reproductive females also showed directed movement towards and around the odour source when exposed to reproductive female odour. These results suggested that round gobies use inter-sexual and intrasexual pheromones and that both sex and reproductive status are important in the detection and release of these pheromones. (c) 2005 Tire Fisheries Society of the British Isles.