SummarySixty wether lambs were divided into 12 lots of 5 each and fed the experimental diets for a 105-day period. The animals were group fed all they would consume twice daily. The variables included in the diets were the presence and absence of potassium acid phosphate (K2HP04), a 10% level of sodium chloride, a 30% level of beet pulp, and the ash of the same amount of beet pulp. Fourteen cases of urinary calculi resulted in the 60 sheep. None of these cases occurred in the 30 sheep which received the 10% level of sodium chloride. Eleven of the 14 cases of calculi occurred in those lots receiving added potassium acid phosphate in the diet, while 3 occurred in its absence. Beet pulp or beet pulp ash had no effect on the incidence of urinary calculi.