Small RNAs were sequenced from the oomycetes Lagenidium giganteum, Phytophthora cactorum, Ph. colocasiae, Ph plurivora, Pythium oligandrum and Py. periplocum. Their characteristics, including 5' prime preference, length and mapping sites, were analysed and used to formulate the hypotheses regarding the role of RNA silencing in the respective organisms. Clonostachys rosea sRNAs were used as outgroup.