The size first maturity, size spawning and spawning season of te octopus Octopus mimus were studied from january 1998 to January 1999. The data used in the analysis correspond to sampling of the artisanal fishery catches in Callao área. The size at firt maturity was 127,7 mm for females and 65,5 mm for males,whose respective weights were 742,5 g and 123,5 g. The mean spawning size was 143 mm for ... [Show full abstract] females and 137 mm for male, with weights of 1 002, and 992 g. The spawning seasons were determined by Gonadosomatic Index (GSI), by Maturity Index (MI) and by the monthly proportion of maturity stages. The monthly evolution of the GSI reveals a main period of spawning in November and a secondary in february – March. The analysis of the MI and the proportion of mature individuals show also a third spawning event in July. The results presented here include a year affected by altered oceagraphic conditions due to El Niño 1997-1998 event. That is why a more exhaustive assessment of normal years and different áreas is needed to have a real knowledge of reproductive patterns of octopus in Peruvian coasts.