This research completes a series of estimates of supply relationships for corn, sorghum, oats, and barley. (See M. E. Ryan and M. E. Abel, "Corn Acreage Response .. .,"Agr. Econ. Res. 24(4); 102-112, Oct. 1972, and "Supply Response of U.S. Sorghum Acreage ...,"Agr. Econ. Res. 25(2); 45-55, April 1973). Special emphasis is on measurement and analysis of the effects of Government commodity programs on acreage planted to each crop. The model developed was employed to estimate 1972 acreage. Actual and estimated values are 20.5 and 20.6 million acres, respectively, for oats and 10.5 and 10.0 million acres, respectively, for barley.