In this work subcooled film boiling on a horizontal disc was studied analytically/numerically. Linearized stability analysis of a vapor film underlying a pool of heavier liquid was performed in three-dimensional, cylindrical coordinates. From the analysis the dominant wavelength and configuration of vapor releasing nodes was identified. Complete numerical simulation of the nonlinearly evolving interface have been carried out in axisymmetric coordinates. Finite difference method was used to simultaneously solve the equations governing conservation of mass, momentum, and energy in the vapor and liquid phases. The equations for the two phases were coupled through the matching of normal and tangential stresses and continuity of mass and energy at the interface. Second order projection method was employed for decoupling velocities from pressure. Numerical grid generation method was utilized to construct a grid system which was aligned with the interface. From the simulations the shape of the nonlinearly evolving interface, the growth rate of the interface, the flow and temperature fields in the vapor and liquid, and rate of heat transfer from the wall and into the subcooled liquid have been determined.