The distribution of the cotton plant root system in the upper 20 cm layer of soil was studied at three different times (42, 61 ond 81-day old plants). These studies were carried out in a cotton field of the variety IAC 12-57/566 planted on a "terra-roxa-misturada" type of soil. The spacing was 80 cm between rows and 15 cm between plants in the row. The method employed consisted in excavating a ditch at a right angle to the plant rows, including four plants, and then removing the soil as blocks. Five loyers of soil blocks were taken: the first and second were 3 cm thick; the third, 4 cm thick; and the fourth and fifth, 5 cm thick. After washing off the soil of each block, the roots in it were air dried and weighed. A representation of the root distribution os encountered is given in figure 2. Far the cotton field studied, most of the roots were found between 3 and 15 cm of depth up to a distance of 25 cm from the plant stem. Between 42 and 61 days of oge, the cotton plants developed an appreciable amount of roots in the soil layer lying between the depths of 3 and 6 cm. It is recommended that much care must be taken in regard to cultivating cotton fields since a large amount of roots is found in upper 6 cm layer of soil which is frequently reached by the cultivator.