Complete condensation of nonazeotropic binary mixtures of R11-R113 refrigerants is experimentally studied. The test apparatus consists of two concentric horizontal tubes, with the vapor mixture flowing in the inner tube and the cooling water in the annular space in the countercurrent direction. The composition and the mass flow rate of the binary-component mixture are systematically varied. Through the measurement of the local temperature of the wall, the cooling water and the vapor along the tube axis, the axial distribution of the local heat transfer coefficients are obtained. An empirical equation is derived to correlate condensation heat transfer performance.