A theoretically based, approximate solution for condensation on horizontal, microfinned tubes has been used as a basis to obtain a relation between heat flux and vapor-surface temperature difference for condensation on a vertical plate with sinusoidal microfins. The earlier result was in excellent agreement with experimental data with regard to magnitudes of the heat-transfer coefficient, dependence on fin and tube dimensions, and for a range of fluids with widely different properties. The new equation for condensation on a vertical plate with sinusoidal microfins takes account of the vertical gravity force and the lateral surface tension-induced pressure gradient over the curved fin surface. The equation reduces to the Nusselt result when fin height is zero and to simple area enhancement of the Nusselt result when surface tension is set to zero. Comparisons are made with experimental data for condensation of nitrogen on a vertical surface with sinusoidal microfins.