Boiling heat transfer on porous coated surfaces with vapor channels was investigated experimentally to determine the effects of the size and density of the vapor channels on the boiling heat transfer. Observations show that bubbles escaping from the channels enhance the heat transfer. Three regimes are identified : liquid flooding, bubbling in the channel and drying out. The maximum heat transfer occurs with an optimum vapor channels density and the boiling heat transfer performance is improved if the channels are open to the bottom of the porous coating.