The embryonic development of the cyst nematode,Heterodera oryzicola and its emergence from egg misses was completed within 8 to 9 days. The emerged second stage juveniles were attracted to roots of rice within 24 hr and penetrated the roots within 24 hr. After penetration, the endoparasitic juveniles developed into males within 14 days and white females within 20 days. Orientation of females was equal towards hypocotyl (42%) and root tip (48%) while a few (10%) matured vertically in thin secondary roots or small rootlets. The sex-ratio between males and females was about 1:4. The virgin females secreted a strong male attractant and the males migrated towards the females in response to this stimulus and mated with the females. The eggs were laid in gelatinous matrix secreted by the females within 22 days and the females turned into brown cysts by 24 days. A singleH. oryzicola female laid on an average 198 eggs in an egg mass and retained 120 eggs within the body of the brown cyst. None of the females was left unmated and all of them laid a single egg mass each within 30 days. One life cycle was completed in 30 days and 12 generations occurred in a year.