The icy moons contain several of the ingredients required for habitable worlds including water, organics and energy. This talk first reviews the lines of evidence leading to the conclusion that a liquid water layer is present in the interior of Europa, Callisto, Ganymede, Enceladus and Titan. Then, the fate of organics on Titan is described at the light of recent Cassini observations. Finally, the importance of tidal energy is briefly discussed.