Percentage botanical composition on a weight basis of cattle and sheep diets, and preference ratings for certain plants, for animals grazing on a mature annual range are presented. Composition of the dietary samples was determined by the microscopic point method on forage material collected through esophageal fistulas. The same microscopic techniques were used to determine composition of herbage clipped in the field. Dietary comparisons are made between individual animals, cattle and sheep, morning and evening grazing, grazing on consecutive days, and between lightly and heavily used range. Individual sheep differed more in diet than did cattle. Differences in most dietary components among cattle and sheep decreased as herbage became limited.