Argan (Argania spinosa L.) oil has a high dietetic and culinary value because it consists of high percentage of unsaturated fatty acids, and it is rich in aroma and flavour. The main objectives of this study were to determine the stability of argan oil (55.4% oleic acid and 24.4% linoleic acid) and to compare it to high-oleic olive oil (78.2% oleic acid and 7.9% linoleic acid) and cottonseed oil (19.8% oleic acid and 52.0% linoleic acid) at high temperatures in heating and deep-fat frying conditions. Several quality parameters were tested and compared in time-temperature conditions simulating abuse by heating and deep-fat frying. After frying no change in the contact angle of argan, olive and cottonseed oils was observed, while in other tests (colour index, viscosity, peroxide value, induction period, conjugated dienes content, total polar compounds) the stability of argan and olive oil was better than that of cottonseed oil. Oil uptake of deep-fried potatoes in argan oil was slightly lower than that in olive or cottonseed oil. It was concluded that argan oil can substitute olive or cottonseed oils in deep-fat frying. The aroma, flavour, oxidative stability and the health benefits might 'compensate' for the high cost of the oil. Sensory evaluation of fried french potatoes and their storage stability were not studied, and addition work is needed to evaluate the quality and storage stability of french potatoes fried in argan, olive and cottonseed oils.