This work provides for the first time a description of the reproductive biology of Trachurus picturatus in Portuguese continental waters (between 41º 49' and 36º 57' latitude North). Fish samples, a total of 7409 individuals, between 17.8 cm and 44.3 cm total length, were obtained by bottom trawlers operating on the north western coast of Portugal, between January 2010 and December 2016. The observed sex ratio (♂/♀) was 0.56. Gonads were observed macroscopically and the monthly variations in gonadosomatic index, proportion of actively spawning individuals, hepatosomatic index and Fulton’s condition factor were analysed. Lengths at first maturity couldn’t be determined due to the lack of small fish. Our results seem to indicate that the main spawning season of T. picturatus starts in December and extends until April-May, with a peak in March.