The Nusselt number for cross flow of a mixture of air and vapor over a cylinder was measured at moderate Reynolds numbers (3000-7000) for temperatures from 300℃ to 700℃ and for vapor mass fractions of 0.18-0.35. Results are also presented for a set of three cylinders aligned perpendicular to the flow for the same range of conditions. The effect of the vapor concentration and temperature on the convection coefficients was investigated to develop a modified Zhukauskas correlation. The results show that the Nusselt number increases as the moisture content increases and that the increase is more than could be accounted for by typical models for the property variations of mixtures. The exponent of the vapor concentration term in the modified correlation is 0.145 for the entire data set indicating the importance of the property variation due to the moisture content.