Eggs and larvae of the cutlassfish, Trichiurus lepturus, were collected during the survey cruises of the project FINEP to determinate spawning areas and season. Six cruises were made from 1975 to 1977 in southern Brazil (23º S -29º S). Spawning occurred throughout the year, but intensively in the cruise, May 1976 (autumn). The heavy spawning area was offshore region of Ilha Grande and of Ilha de Sta. Catarina. Mean temperature of the spawning area was 24.09 ºC, ranging from 21.15 to 26.29 ºC and mean salinity was 35.31 ‰, ranging from 35.04 to 35.52 ‰. Catch data of cutlassfish fishery showed a gradual increase last several years in the two states: São Paulo and Santa Catarina.