Hirschmanniella oryzae, i.e. the rice root nematode (RRN), is among the major pests of rice and is the most common plant-parasitic nematode found on irrigated rice. In Egypt, H. oryzae and H. gracilis and other nematode genera were found in association with rice paddy fields. RRN is sexually dimorphic, i.e. sexes are separate and reproduction is amphimictic or bisexual; both sexes are required. The nematode infects and multiplies in the roots of the main host, rice cv. Giza 171, but not in those of cotton, maize, soybean, barley, wheat, Egyptian clover, alfalfa, horse bean and flax. However, the nematode penetrates and multiplies in the roots of several selected annual and perennial weeds. It has been found that RRN can penetrate anywhere along the roots of rice except at the tips or the thin lateral roots. The penetrated nematodes can either enter the root completely or simply embed their heads into the cortex. The rice root nematode makes tunnels after penetration into roots which are almost perpendicular to the root surface. An estimation of rice losses due to the rice root nematode was 25% and a total of 53,734 metric tons of rice grains with a net cash value of 10.7 million L.E. (107 million L.E. according to the present official price of rice ton in 2013) were the losses due to the rice root nematode infestation in Egypt. Control measures of the rice root nematode depend on: (1) varietal breeding for resistance, (2) application of nematicidal chemicals, (3) crop rotation, (4) fallow, (5) tillage and mechanical disturbance, (6) ammonia injection, (7) thermal control, (8) nutrition of rice by slow release rubber fertiliser formulation, (9) organic manure and (10) legislation.