Data on maturity, gonadosomatic index (GSI) and length/weight of Antarctic toothfish Dissostichus mawsoni were collected from Sub-area 88.1 in the 2001-2002 season by the New Zealand bottom longline vessels Janas and San Aotea II operating in the Exploratory Fishery. The onset of the spawning season was identified as late autumn (May). A significant difference in the condition of fish between summer and autumn was noted, and this may be a result of migration f or spawning. The maximum GSI recorded for females was 26% with a 7.5 kg ovary. The maximum GSI was 43% for a stage 3 male weighing 20 kg, with the testes weighing 8.6 kg.