The mineral content of saliva was studied in 2 groups of patients; one of diabetic children having resistant teeth and arrested caries, the other of unselected hospital patients showing as a group marked caries and soft teeth. The variations noted in the calcium, phosphorus, chlorides and pH of the saliva were similar in both groups, indicating that the formation of salivary calculus, and the arrest of dental caries noted in the diabetic children under dietary control, are probably not due primarily to any marked differences in the mineral content of the saliva.