In Florida and Cuba the stone crab Menippe mercenaria (Say, 1818) is under strong fishing-pressure; nevertheless in the Mexican Caribbean it is considered as sub-utilized and poorly known resource. Artificial shelters ("condominios cubanos") were used to study relative abundance, age structure, claw length-carapace amplitude relation, and population in three seasons and four sectors at Bahia Ascension, Quintana Roo, Mexico. The abundance varied according to the sector and sampling season: population was higher in the south and during the north wind ("Nortes") season (January to March). The carapace amplitude was directly proportional to claw length (r² = 0.83, 0.97 and 0.89; p< 0.05 in females, males and total, respectively). The results sugest that specimens with 37.5 and 67.5 mm of carapace amplitude are the most limited regarding refuge availability in the Bay