Studies were made on the seasonal variation and qualitative composition of the Appendicularia population from a limited area of the South Atlantic 25º09.5'S to 24º04.0'S latitude and 47º48.4'W to 46º00.4'W longitude at the São Paulo State coast off Cananéia and off Santos. The pattern of the seasonal variation was irregular for the most important species (O. longicauda). Some qualitative differences regarding the species composition are discussed.