To study the diversity of Oomycota from the "Reserva Biológica de Paranapiacaba", water and soil samples were collected, every three months, from November/2003 to November/2004 and baited with cellulosic and keratinous substrates. Of the 175 isolations, 35 species were identified, six of which are mentioned for the first time to Brazil descriptions, illustrations and comments are provided for them. One belongs to Leptolegniellaceae (Leptolegniella exogena Karling), one to Pythiaceae (Pythium helicandrum Drechsler) and four to Saprolegniaceae (Achlya treleaseana (Humphrey) Kauffman, Leptolegnia subterranea Coker & Harvey, Saprolegnia blelhamensis (Dick) Mil'ko and S. terrestris Cookson ex Seymour).
Atlantic Rainforest; diversity; Oomycetes; Reserva Biológica de Paranapiacaba
