The cavernicole asellid Asellus cavaticus Leydig has been reared in our laboratory for more than twenty months, permitting us to give some data on the sexual cycle of this species. Females provided with brood pouches seem to be more numerous in the spring, as is the case with the subterranean amphipod Niphargus virei Chevreux. The average length of the incubation period seems much shorter than that of other troglobitic species such as Niphargus virei Chevreux or Caecosphaeroma burgundum Dollfus, so that the life cycle of our species is nearer to that of epigean Asellus. The number of young per brood appears to be related to the length of the female, as is suggested by our observations on 52 ovigerous females, but there must be other factors which influence this quantity. The comparison between our observations and those made on the North American cavernicole Asellus tridentatus Hungerford shows that the sexual biology of these two species is apparently quite different.