The present study describes the reproductive cycle and population structure of the intertidal crab Petrolistheslaevigatus, an abundant inhabitant of the upper rocky intertidal zone, as well as the relationship betweenseasonal patterns in the release of its planktonic larvae and recruiting. A total of 22900 individuals wascollected along the coast of southern Chile between May 2001 and March 2003.The structure and density ofthe adult population (males and females) was relatively constant throughout the study period, althoughseasonal variations were observed in these two parameters of the benthic population (males, females, juvenilesand megalopae), principally due to the incorporation of new individuals (recruitment) into the intertidal zone.Petrolisthes laevigatus presented a prolonged reproductive period. Females with initial eggs were present from theend of summer through to the middle of the following summer (11 months) and the breeding season lastedseven months (from August to February), as reflected in the six months of intertidal settlement (October–March).The interannual patterns and variations observed in the settlement along the southern Chilean coastlinewere related to the patterns in the abundance of potential released planktonic larvae. Petrolisthes laevigatus,unlike most temperate species, has a broad reproductive and settlement period in the south of Chile, whichallows a highly stable structure and population abundance in this intertidal zone.