The lipid and fatty acid composition of the mesocarp and seed of avocado fruit grown and harvested in Japan, which is located at the northern range of the avacado, was investigated and compared to an imported avocado purchased commercially. The potential of the avocado mesocarp as an agricultural product in Japan was also explored. Total lipids (TL) accounted for approximately 20% of the mesocarp. Further analysis showed that the neutral lipid (NL) fraction accounted for at least 95% of the TL, and almost 90% of NL was triacylglycerol. Monoenoic acids accounted for at least 65% of the total fatty acids, and oleic acid, which is regarded as an especially important functional component of avacado accounted for approximately 50% of the monounsaturated fatty acids. A comparison of the Japanese avocado cultivars and an imported avocado cultivar in the present study revealed no significant differences in the lipid and fatty acid compositions. Therefore, production of avocado fruit, which is rich in various nutritional components, is expected to be increased on a larger number of farms in Japan in the future. It is believed to be necessary to carry out further verification, such as the establishment of a cultivation technique adoptable to Japan, examination of optimal soil and land features, and cultivar selection.