Senscence is sorghum [Sorghum bicolor (L.) Moench] is manifested as pre‐mature shedding of the lower plant leaves. This process occurs during grain filling and is much more pronounced in senescent than in nonsenescent cultivars. Since roots are the plant organs responsible for water and nutrient accumulation, it is important to understand their relationship to total plant development. The root development of a senescent and a nonsenescent hybrid grain sorghum was investigated in the field. The purpose of this investigation was to determine the influence of senescence on root distribution of two grain sorghum hybrids. Root samples were collected on approximately biweekly bases to measure their rate of growth and extent of distribution. Samples were collected on both sides of, and perpendicular to the row at 5‐, 15‐, 22.5‐, and 30‐cm intervals to a depth of 105 cm. Root distribution and density were similar for each hybrid 3 weeks after planting (3 June). The nonsenescent hybrid, represented by ‘ Pioneer 42004’, established its aventitious root system earlier than did the senescent hybrid, represented by ‘Pioneer 22516’. Differences were based on visual inspection of the roots and root diameter measurements. Root density of both hybrids increased until grain filling with the senescent cultivars generally exhibiting greater root density. From week 11 (5 August) to week 13 (19 August), both hybrids decreased in root density with a greater decrease noted for the senescent hybrid. The more dramatic decrease in density for the senescent hybrid was also reflected in a lesser grain yield.