A method for calibrating a temperature sensor arranged in a vapor compression system is disclosed. The opening degree of an expansion device is alternatingly increased and decreased. Simultaneously a temperature of refrigerant entering the evaporator and a temperature of refrigerant leaving the evaporator are monitored. For each cycle of the opening degree of the expansion device, a maximum temperature, T1, max, of refrigerant entering the evaporator, and a minimum temperature, T2, min, of refrigerant leaving the evaporator are registered. A calibration value, ΔT1, is calculated as ΔT1=C−(T2, min−T1, max) for each cycle, and a maximum calibration value, among the calculated values is selected. Finally, temperature measurements performed by the first temperature sensor are adjusted by an amount defined by ΔT1, max.