Calcium-phosphorus ratios of 1.31, 4.3:1, 9.1:1, and 13.7.1 were fed to steer calves. The P in all rations was approximately 12 g per calf daily. Ca in the rations was varied by adding ground limestone. Gains decreased as the Ca in the rations increased, and if gains are used as a criterion, a critical calcium-phosphorus ratio may exist between 4.3:1 and 9.1:1. The excessive Ca intake was not reflected by a change in the blood plasma Ca levels. In trial I, the terminal inorganic P in the plasma did differ significantly between treatments. In trial n, the terminal inorganic P in the plasma did not differ dignificantly. The inorganic P content was not depressed below a level considered adequate for proper nutrition. Thus, the excess Ca appeared to depress gains by interferring with the digestibility and/for absorption of nutrients and mineral elements other than P.