The oxygen analysis of solid wastes is one of the important ultimate analysis necessary to determine: the efficiency of operation of an incinerator, the design of furnaces for incineration, and a complete materials balance of incoming and outgoing material. The oxygen content of solid wastes samples must be known if their calorific values are to be calculated from ultimate analyses. The two new formulas for calculating total oxygen content in solid wastes samples correlate data from as many as eight different analyses. These eight components are: total carbon, carbonate carbon in total sample, carbonate carbon in ash from volatile at 600C, total hydrogen, total nitrogen, total sulfur, total chlorine, and a volatile at 600C or at 950C value. The oxygen method, described herein, deals with the procedures for the eight related components. The new formulas for oxygen concentrations still have the errors inherent in the other analyses, particularly the volatile analysis; however, they do take into account carbonate oxygen which could cause the greatest inaccuracy in total oxygen data for solid wastes samples. The recommended procedure for determining carbonate oxygen and organically-bonded oxygen is: first determine carbonate carbon, multiply this answer by four for carbonate oxygen, and then obtain the organically-bonded oxygen content by subtracting the carbonate oxygen value from the total oxygen concentration.