Observations on reproduction in both wild-caught and laboratory-maintained Dasykaluta rosamondae have led to the conclusion that this species is one of 10 dasyurid marsupials in which males die soon after their first mating period. D. rosamondae have a short annual breeding season. The females are monoestrous, mating in September and bearing the young in November. Laboratory-reared young are weaned at an age of about 3 1/2-4 months, in February and March, and juveniles appear in the field population at this time. Both mates and females reach sexual maturity at an age of about 10 months. In the laboratory, males breed in only one season, after which those that survive become reproductively senile. Mature males disappear from the field population about the time the young are born; those collected shortly before this show signs of reproductive senescence. Males collected in the months after the young are weaned represent a single age-class; their reproductive development parallels that of maturing known-age males. Females are capable of breeding in at least two seasons and litters of up to eight are reared. Development of the pouch young is described. Unusual interstitial tissue masses develop in the ovaries of D. rosamondae; the granulosa cells of some follicles undergo transformation to interstitial cells, and the oocytes in these follicles degenerate, shortly before the females enter oestrus.