We report a case of cohabitation between an adult male and a conspecific subadult female Lycosa tarantula (Linnaeus 1758) (Araneae, Lycosidae). Cohabitation was observed during a field study in a population near Madrid city (central Spain). The male was first observed in the female burrow four days before the female maturation molt. Both individuals remained together until female maturation occurred. Mating occurred two days after female maturation, at a much younger age than non-cohabiting females. The possible mechanisms by which adult males find subadult female burrows are discussed.