A number of different chemical substances were evaluated for their ability to depress dolomite in the flotation of apatite and collophane from dolomite. Carboxymethyl cellulose was found to be the best depressant and citric acid and naphthyl anthyl sulfonates were found to be good depressants for dolomite. None of these substances significantly depressed apatite or cellophane. EDTA was found to be a dolomite activator rather than depressant. The other chemicals studied had little effect on either dolomite or apatite flotation.