Fresh fish obtained from commercial landings in the harbours of Olhão and Quarteira (south Portugal) in 1998 and 1999, were examined in order to study different aspects of the reproductive biology of Microchirus azevia (Risso, 1810): spawning season, ovary maturation, length/age at first maturity and sex ratio. A five-stage maturity scale, based on external appearance was used to classify the ovaries. M. azevia is a winter-spring batch spawner with a protracted spawning season. Females outnumbered males in length classes greater than 19 cm and in all age groups. The estimated mean size at first maturity (L50%) for females was 23 cm total length at 3 years of age (t50%).