Fatty acid composition and $C_{18:2}:C_{18:3}$ of soybean seed and sprout is important for soy-industries to manufacture quality products. Six soybean varieties were analyzed by gas chromatography to determine fatty acid composition and linoleic to linolenic acid ratio ($C_{18:2}:C_{18:3}$) in seed, sprout, and their structural parts. In the case of whole seed and its structural parts, significant variation in fatty acid composition and $C_{18:2}:C_{18:3}$ were observed between varieties except palmitic acid $(C_{16:0})$, while all the parameters were significantly different for seed parts. Significant interactions of variety with seed parts were observed for oleic acid $(C_{18:1})$, $C_{18:2}$ and $C_{18:2}:C_{18:3}$. The highest saturated fatty acid, $C_{18:1}$ and polyunsaturated fatty acid were recorded in seed coat, cotyledon, and seed axis, respectively. The lowest $C_{18:2}:C_{18:3}$ was found in seed axis. In the case of sprout study, variety had significant effect on all the parameters observed for whole sprout, cotyledon, root, and except $C_{18:3}$ for hypocotyl. Culture days had significant effect on $C_{16:0}$, $C_{18:2}$ and $C_{18:3}$ in whole sprouts, while only on $C_{18:3}$ and $C_{18:2}:C_{18:3}$ in cotyledon. For hypocotyl, culture days had significant effect on $C_{18:1}$, $C_{18:2}$ and $C_{18:2}:C_{18:3}$, however, $C_{16:0}$, $C_{18:1}$, $C_{18:3}$, and $C_{18:2}:C_{18:3}$ were significantly different in root. In sprout, days and variety interacted significantly for $C_{16:0}$, $C_{18:3}$ and $C_{18:2}:C_{18:3}$, and $C_{18:1}$, $C_{18:2}$, $C_{18:3}$, and $C_{18:2}:C_{18:3}$, respectively for whole, cotyledon, and root. The significantly lowest $C_{18:2}:C_{18:3}$ (1.1) was observed in hypocotyl and root of Hwangkeumkong in 5 days. Knowledge of fatty acid composition and $C_{18:2}:C_{18:3}$ of seed, sprout, and their parts could be applicable for oil and other soy-food industries to make quality products.