In any kind of refrigerator, frost and ice formation has to be limited by defrosting of the evaporator surface. This paper proposes the use of fiber-optic sensor technology to successfully achieve the goal of sensing and controlling ice formation inside refrigerators, by monitoring ice thickness and servocontrolling the defrosting cycle. The main advantages of such a choice are discussed. Different fiber optic sensors are analyzed. An experimental investigation on a test bench and inside a real refrigerator is performed. The problem of cost of the sensor is also addressed.