The removal of arsenic from colemanite ore containing arsenic by the froth flotation was studied. Flotation experiments were carried out in two stages. First, the effects of flotation time, the gas flow rate, particle size, the solid-to-liquid ratio and temperature without adding any conditioning reactivities were investigated. Later, the effects of the kinds and concentrations of the collector, frother and control reagents, and their combinations were examined. By using the most convenient parameter values, it was found that the recovery percentage of the ore and the removal percentage of arsenic can reach 75.50% and 90.31%, respectively.