Studies were made of the root distribution of Dolichos lablabin a reddish-yellow podzol (massapê-salmourão) soil in the State of São Paulo. Twenty eight percent of the roots by weight were found in the upper 20 cm layer of soil. The rest, uniformly distributed down to the maximum depth, reached 3.4 m. It was calculated that when the crop is planted at a 0.2m x 0.5m spacing, it leaves 1.5 tons of roots in the soil, per hectare.