Pythium rot of Sansevieria trifasciata Pramn ‘Laurentii Compacta’ occurred in Hachijo-island of Tokyo Metropolis in 1999. A Pythium sp. isolated from the diseased plants was identified as Pythium spinosum Sawada. Inoculation tests showed that this fungus was the causal agent of the disease. This is the first report of the disease in Japan.