Because the meagre (Argyrosomus regius) is not currently found around the Balearic Islands (western Mediterranean), the Balearic government is carrying out a restocking programme to recover its population. The success of this programme is critically dependent on improved knowledge of the meagre’s life cycle, and particularly its reproductive biology. Data on key reproductive parameters based on both reared and wild specimens are reported here. Histological examinations and gonadosomatic indices from 342 reared specimens demonstrated that 1) the potential reproductive season ranged from April to June and peaked in May, and 2) length at maturity (L50) was 49.3 cm for males and 57.2 cm for females, age at maturity (A50) was 2.7 years for males and 3.5 years for females, and weight at maturity (W50) was 1396 g for males and 1892 g for females. Histological examinations of 37 wild fish from Cádiz (SW Spain) demonstrated that the meagre has determinate fecundity. The annual potential fecundity of reared females ranged from 0.9 to 4.2 million oocytes, which is exponentially dependent upon female size.