Mephosfolan is frequently used in India as a seed treatment to protect rice against insect pests such as whorl maggot [Hydrellia sp.] and green leafhopper [Nephotettix virescens (Dist.)], but little is known about its effect on germination. In the laboratory at the Madhya Pradesh Rice Research Institute, rice seeds of the Taichung variety were soaked in solutions of mephosfolan at 250, 500, 750 and 1000 p.p.m. in water for 24 h, washed 3 times and germinated on blotting paper for 7 days. At up to 750 p.p.m., the compound had no adverse effects on germination or growth, but at 1000 p.p.m. it reduced germination by 35% and reduced the length of both root and shoot in seeds that did germinate; the reduction in shoot growth was particularly marked, the length after 7 days being only 1 mm as compared with 12 mm for the shoot from seeds treated at 500 p.p.m. and 14 mm for the shoot from untreated seeds.