Nuts of walnut (Juglans regia L.), cultivated in the district of Denizli (altitude of 300 m) and Cameli (altitude, 1200 m) in the Aegean region of Turkey, were used to determine the effects of altitude on fruit quality and the force and energy required to crack the nuts. The varieties used were Bilecik, Sebin, Yalova-1, Yalova-3 and Yalova-4. For all cultivars, walnut trees grown at the higher altitude produced small size nuts with thick shells. Based on the average for all cultivars, kernel removal quality decreased with high altitude. The nuts obtained from the high-altitude location were lighter-colored and required more force to fracture the nuts than those harvested at the low altitude. The amount of energy required to crack the nuts was higher for the nuts grown at the low-altitude location except for the cultivar, Sebin.