The effects of length of run on water intake, soil water distribution, grain sorghum yields and irrigation water use efficiencies were evaluated on graded, furrow-irrigated Pullman clay loam in 1961-3 and in 1955-66. Grain yields were reduced with length of run, but reduction was smaller than the reduction in water intake; water use efficiency therefore increased with length of run, from 306 lb grain/ac-in for the upper 600-ft run to 479 lb for the lower 600-ft run. Grain yields declined with length of run: from 7880 lb/ac from the upper third to 7230 lb in the lower in 1961, and from 7130 to 6540 lb in 1962. In 1965, a year of higher rainfall, yields were 6750, 6800 and 6640 lb/ac for the upper, middle and lower sections of a run 1800 ft in length.