A sclerotinia rot of Water cress (Oenanthe javanica) occurred in the commerical farmers field at Garye-myon, Uiryeong-gun, Gyeongnam Province, Korea, 2002. The typical symptoms appeared on leaves and stems. At first, the infected leaves or stems turned dark green later become watery soft rotted; white fluffy mycelia grew from the lesion, later formed black sclerotia. Sclerotia on the infected plants and PDA medium were globose to cylindrical or irregular in shape and 1.0~10.7 1.0~7.6 mm in size. Cup-shaped aphothecia with numerous asci were formed from sclerotinia and the size were 0.4~1.6 cm in diameter. Asci with 8 spores were cylindrical and 74~236 4.2~24.8 m in size. Ascospores of one cell were hyaline, ellipsoid to ovoid in shape, and 8.3~12.4 3.6~7.2 m in size. The optimum temperature for mycelial growth was , and sclerotinia forma-tion was between 15~. On the basis of mycological characteristics and pathogenecity test to host plants, the fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia sclerotiorum caused sclerotinia rot on Oenanthe javanica caused by in Korea.