Technical Abstract: Biodiesel is a renewable and clean-burning fuel which can be produced by transesterification of plant oils. One hundred peanut accessions (landraces or cultivars) from two subspecies and six botanical varieties and two soybean accessions were selected and planted in 2008. The oil content and fatty acid composition was analyzed and compared. Within the subspecies hypogaea, seeds from the botanical variety hypogaea contained a much higher amount of oil in seeds (51.98%) than seeds from the botanical variety hirsuta (47.25%). For the fatty acid composition, the botanical variety hypogaea contained a much higher amount of oleic acid (49.08%), much lower amounts of palmitic acid (9.71%) and linoleic acid (30.79%) than the botanical variety hirsuta (37.68%, 13.84% and 40.23%, respectively). In comparison of the oil content, peanut seeds contain a much higher amount of oil (49.434%) than soybean seeds (23.28%). Significant variability in oil content (41.71% - 56.20%) was detected among peanut accessions. In comparison of the fatty acid composition, peanut seeds contain a much higher amount of oleic acid (43.61%) than soybean seeds (28.82%), and a much lower amount of linoleic acid (34.94%) than soybean seeds (49.07%). The major differences in fatty acid composition imply fewer double bonds present in peanut oil than in soybean oil. In other words, peanut oil is less susceptible to oxidation than soybean oil. Significant variability in oleic acid (33.44% - 54.91%), linoleic acid (24.94% - 44.92%), palmitic acid (8.77% - 15.69%), and stearic acid (1.64% - 5.63%) was detected among peanut accessions. Significant negative correlations of oleic acid with palmitic and linoleic acids were detected. Our results indicated that higher oil content and better fatty acid composition of peanut seeds make it a better industrial oilseed crop for biodiesel production. Moreover, based on the variability detected in oil content and fatty acid composition among peanut accessions, there is potential to increase oil content and alter fatty acid composition through peanut breeding programs.