The development of the root system on five varieties of rice grown under upland conditions, has been studied. It has been found, with the rice varieties used and under the conditions tested, that 66 percent of the roots occured within 5 centimeters and 95 percent within 15 centimeters of the surface of the ground. A few roots were found to reach a depth of 1 meter, and occasionally to a depth of 1.35 meter. The Iguape-catete variety of rice showed a tendency to develop a somewhat deeper root system than the other varieties studied. Recognition of the fact that development of the roots of the rice plant is largely within the plowed layer of soil, suggests that deep plowing prior to planting with frequent and shallow cultivation following planting, to eliminate weed competition, would be desirable.