Heat transfer from a horizontal heated rotating disk to a thin water film flowing over it was investigated. A series of experiments were carried out to determine Nusselt numbers on the disk both with and without evaporation from the liquid film surface. The Nusselt number increased with increasing disk rotation rate, water temperature, and water flow rate, while evaporative cooling from the liquid film surface only had a moderate effect on the Nusselt number magnitude. Functional dependence of the Nusselt number from an accompanying semi-analytical model and experimental data were used to develop semi-empirical correlations for the Nusselt number.