This study clarifies the applicability of a sensory evaluation to easily determine the life span of frying oil on the fried food cooking in the kitchen. Two types of foods, i. e. , a chicken fillet and potato, were deep-fried coated with two types of flour, i. e. , potato starch and wheat flour. Frying was continued until the flavor score of the oil had dropped to 3. A sensory evaluation of the frying oil and each fried food was then carried out. The life span of the frying oil to reach the flavor score of 3 was slightly longer for the potato compared to the chicken fillet. It was suggested that the scores for the viscosity and rancid flavor of the frying oil corresponded to the flavor score result of the frying oil. The flavor and taste of the potato fried in the oil with a flavor score of 3 were not good. However, it was difficult to judge the degradation by the appearance of the fried chicken fillet coated with potato starch. The flavor score of the frying oil corresponded to the rancid flavor of the frying food in any case. The color of the frying oil and the taste of the fried materials varied case by case. These results suggest that the flavor score of the frying oil is a useful and easy method to determine the life span of frying oil in the domestic kitchen when a potato starch or wheat flour coating is used.