A correlation of vapor-side heat transfer coefficients is proposed for condensation of a steam-air mixture on a vertical surface. The correlation is based on the analogy between heat and mass transfer and includes the effects of the wavy interface between a condensate film and bulk vapor on the condensation. For a film Reynolds number less than 350, the vapor-side heat transfer coefficients are wen correlated as a function of vapor Reynolds number, air-mass fraction, Prandtl number, and Schmidt number within +/- 10% error. The ratio of the enhanced heat transfer coefficients for the wavy interface to those with a him Reynolds number less than 350 is well correlated as a function of film Reynolds number and vapor Reynolds number within +/- 15% error. The him Reynolds numbers range from about 40 to 17,600 and the vapor Reynolds numbers from about 77,000 to 500,000. The air-mass fractions also range from 0.1 to 0.7.