We study wetting of planar surfaces by a chiral nematic (cholesteric) liquid crystal. The wetting transition is well known for nematic liquid crystals. At the nematic-isotropic coexistence temperature, a thin liquid crystal layer forms at the substrates. As the anchoring constant is increased, the layer thickens and, at the transition anchoring constant, complete wetting occurs. Here, we study how the chirality of the cholesteric influences the wetting transition and the configuration of the liquid crystal film, by numerically minimizing the Landau-de Gennes free energy.