The nonhydroxy fatty acid composition of rat brain lipids (except gangliosides) was determined by support-coated open-tubular (SCOT) gas chromatography. Fatty acids of both odd and even chain lengths ranging from C14 to C26 were detected. Brain lipids contained 49% saturated, 29% monounsaturated, and 22% polyunsaturated fatty acids. Monoenoic fatty acids were mainly of the ω-9 and ω-7 series with minor amounts of ω-10 and ω-11 isomers. Dienes and trienes consisted of ω-6, ω-7, and ω-9 series. Tetraenes were of the ω-6 series. Small amounts of ω-6 and ω-3 pentaenes were detected. The most abundant polyunsaturated fatty acid was 22:6ω-3. The advantages of support-coated open-tubular columns over wall-coated open-tubular columns for the analysis of brain lipid fatty acids are discussed.