Using microflotation method, this study explored the collectorless flotation of Chalcocite and its dependence on the redox potential of pulp . Electrochemical studies were performed by cyclic voltammetry in specific potential ranges and at different pH values. The results show that significant floatability of Chalcocite occurs in the specific reducing conditions. By increasing potentials, on the other hand, the floatability of Chalcocite is reduced. The effect of pH was also examined: At pH=4, the maximum recovery of 73%, was obtained at E= -222 mV (Eh= -17); and at pH=9, the maximum recovery of 71% was obtained at E= -501 mV (Eh= -296). On the basis of the results obtained, the possible mechanisms of collectorless flotation of Chalcocite in different conditions were discussed.