Munida subrugosa was sampled monthly from November 1997 to November 1999 in the Beagle Channel by means of an epibenthic trawl. The reproductive cycle started in May, reflected by the occurrence of ovigerous females. Maximum size of oocytes, maximum value of gonadosomatic index in females (16·8 g mm carapace length [CL]−1) and males (1·6 g mm CL−1), and the proportion (∼70%) of ovigerous females with full egg-clutches occurred in June. Since the proportion of ovigerous females in October was ∼5% and the planktonic larvae reportedly hatch in September, the embryonic development lasted ∼90–120 days. Females and males attained physiological maturity at 9·9 and 8·0 mm CL respectively, and males reached morphometric maturity at 24·4 mm CL. Fecundity was correlated with female size (r=0·85) and was between 124 and 10,750 eggs per female. Average diameter of recently extruded eggs was 0·69 mm (SD±0·06 mm). At the beginning of the reproductive cycle, ovigerous females had partial broods of ∼300 eggs, which represented <5% of complete clutch.