We describe the distribution of males and females in a natural population of crested newts, Triturus cristatus, during the breeding season and show that the mating system is a lek. Males arrived earlier than females at breeding sites, and throughout the breeding season there was a male-biased operational sex ratio. Males aggregated for most of the breeding season, and did not cluster over any resources essential for females. The male aggregations were not correlated with environmental factors, nor with female distribution. The males display to females prior to mating, but contribute nothing apart from sperm, and they cannot force females to mate. Females also aggregated, though less than males, and their aggregations were separate from those of males.