In the research conducted in the years 2008 – 2009, the effect was assessed of the habitat conditions on the content and fat yield, as well as the on the composition of fatty acids in the grain of two naked oat (cv. Krezus, cv. Ród 7105), and two husked oat (cv. Polar and cv. Ród 7505) genotypes. The field experiments were located in the Podkarpackie Province (Dukla, Lubliniec Nowy, and Przecław), at the stations with varying soil and weather conditions. The varying habitat conditions had not any significant effect on the content of fat in oat grain (4.71 – 4.89.) during the analysed vegetation seasons. Between the genotypes analyzed, there were found significant differences in the fat content in the grain. The naked oat cultivars (Polar cv. – 5.20 % and Ród STH cv.: 7505 – 6.32 %) contained more fat (32 % more) than the husked cultivars (Krezus cv. – 3.88 % and Ród STH7 cv.: 105 – 3.90 %). The oat fat yield from one area unit depended on the weather conditions, location of the experiment, and genotype. Between the genotypes compared, the most significant difference was found in the content of fatty acids. The short-straw naked oat Ród STH7505 cv. contained the highest amount of oleic acid (41.50 %) and the lowest amount of linoleic acid (38.00 %) and linolenic acid (0.99 %). The husked Krezus cv. had the lowest amount of oleic acid (37.05 %) and the highest contents of linoleic acid (40.71 %) and linolenic acid (1.39 %).