Three annual forage legumes, apparently differing in their drought resistance in the field, were grown in controlled environments to better understand mechanisms of their drought resistance and to determine relationships between phosphorus nutrition and drought. Phosphorus fertilization stimulated growth of the annual legumes and decreased water use (ml/g dry weight of top growth). Relative top growth and phosphorus uptake of Spanish clover tended to confirm observations of its drought resistance in the field. Water use was higher in Spanish clover than in subterranean clover and therefore does not appear to contribute to its drought resistance. This study provides information that will be helpful in future research on the morphological and physiological traits that contribute to drought resistance in these and other range plants.