This qualitative survey of the Oscillatoriaceae (Cyanophyceae) from Sa
o Paulo State, Brazil is based on the study of nearly 600 samples coll
ected from aquatic, subaerial and terrestrial environments. Ten genera
and ninety infrageneric taxa are identified on the classical grounds
of vegetative morphology. 18 taxa are recorded for the first time for
Brazil, and 29 are new records for Sao Paulo State. Geographical distr
ibution is given.