In this paper, the Optimal Homotopy analysis method (OHAM) has been used to derive a highly accurate analytic solution for the steady three-dimensional problem of a condensation film on an inclined rotating disk. With a similarity solution method, the governing equations can be reduced to a system of nonlinear ordinary differential equations (ODEs). The control parameter (ħ) in the HAM is derived by using the averaged residual error method. Using the optimal control parameter provides a superior control on the convergence and accuracy of the analytical solution. The velocity and temperature profiles are shown and the influence of Prandtl number on the temperature profiles is discussed in detail. The validity of the obtained solutions is verified by the numerical results.