Abstract: The present invention relates to a defrosting device, for a refrigerator with a number of cooling compartments, which only supplies heat to the evaporator in the fresh food compartment when strictly necessary, that is, when fast defrosting is required, whereas it provides for natural defrosting as long as this is sufficient. In a first arrangement, fast defrosting is performed each cooling cycle but only for part of the time the compressor is off and only after a given temperature threshold has been exceeded by the evaporator in the fresh food compartment or by the freezer. In a second arrangement, fast defrosting is only performed for one out of "n" number of cycles. Both these arrangements provide for energy saving as compared with known technology besides improving fast freezing performance by reducing food freezing time again as compared with known technology.