Gonads of 1991 bogues, Boops boops (Linnaeus, 1758), caught off the western coast ofPortugal (Peniche) and 1716 off the southern coast (Algarve), and measuring 6-36 cm total length, were used to analyse sexual maturity. Study of the annual sexual cycle showed that: a) females from Peniche and Algarve started the sexual cycle about one month later than males; b) in Algarve, both females and males initiated and finished their sexual cycle earlier than females and males from Peniche; and c)the spawning season occurred between February and May in Algarve and between March and June in Peniche. The gonadosomatic index allowed greater precision on definition of maturity stages and confirmation of the spawning season. Thehepatosomatic index showed that the liver seemed not to have a direct influence in vitellogenesis. The relative condition factor was not affected by the annual sexual cycle as was revealed by the small oscillations of its value occurring between January and July. Length at first maturity varied between 13 and 15 cm, depending on whether males from the southern coast or females from the western coast were considered.