Biochemical changes in rice varieties Annapurna, Manika and Ramakrishna showing susceptible, moderately resistant and resistant reactions, respectively to the root knot nematode Meloidogyne graminicola were studied six weeks after inoculating the plants with the nematode @ 1000 J 2 plant^-1. Chlorophyll content decreased by 60.7, 24.9 and 1%; root sugar increased by 43.8, 17.7 and 10.7%; shoot sugar decreased by 26.5, 28.8 and 10.8%; root nitrogen and protein increased by 27.1, 30.4 and 4.3%; shoot nitrogen and protein decreased by 22, 16.6 and 2.4%; root phosphorus decreased by 34.8, 9.8 and 10.6%; shoot P decreased by 25.2, 6.7 and 1%; root potassium decreased by 16.5, 56.% and 73.1%; shoot K decreased by 59.6, 18.9 and 22.7%, respectively in the test varieties.