The cardinalfish (Epigonus crassicaudus) is a long-lived and endemic deep-water fish inhabiting the central and southern coast off Chile. Knowledge about basic biological attributes including maturity aspects is fragmentary in this species. The historical and comprehensive data available are applied to provide a detailed study of the reproductive biology of the female cardinalfish. The gonadosomatic index was computed from 5110 female gonads collected by onboard scientific observers between October 2000 and December 2012. A total of 1467 females gonads collected between March 2007 and December 2009 were subjected to histological analysis of maturation upon which a maturity ogive was estimated. The ovarian development of this specie is asynchronous, characterized by a continuous reproductive cycle in which reproductive activity is found throughout the year with a maximum during the austral autumn and summer (between May and June). Length at 50% maturity was estimated in 23.2cm of fork length (95% CI: 21.7-23.9cm). The results presented here are compared with previous sparse estimates available for this species.