The effects of different dietary levels of peppermint leaves on productive performance, egg quality and serum biochem-istry showed that 12 weeks administration of these leaves have beneficial effects on egg production, egg weight, egg mass,feed intake, FCR, HU, eggshell and serum cholesterol during the late laying period in Hy-Line brown hens. More detailedstudies are needed in future to determine the optimal dietary inclusion level and its economic impact.