During the 1983/84 growing season, stem rot was detected on Chilean rice. Symptoms observed varied from a small blackish lesion in the leaf sheaths to plants with culms infected internally. Sclerotium hydrophilum Sacc. (identified by the Commonwealth Mycological Institute, under Nº 285103) was isolatefrom plantsthat presented the symptoms and sclerotia.These, grown in PDA 2% produced abundant new sclerotia, in aproximately 7-10 days. The diameters of the sclerotia were 311 ± 51.7 μ. Rice plants, with and whithout injury, were inoculated with 0, 5, 20 and 40 sclerotia/ plant. In the two last treatments, plant death was produced; and ah inoculated plants produced abundant sclerotia, that were similar in lenght, form and colour to those under study. It was concluded that the stem rot symptoms observed on rice in Chile, were caused by Sclerotium hydrophilum Sacc.