Changes in fatty acids were studied during maturation of Coriandrum sativum seeds. The seeds matured in 50 days after flowering.Lipid synthesis proceeded at a steady rate up to 40 days after flowering. Reductive ozonolysis of the monoenes followed by gas liquid chromatographic analysis of the atdehydic fragments as dioxolanes of 1,3-propanediol was employed to estimate petroselenate (octadeca-cis-6-enoate) in the presence of oleate (octadecacis-9-enoate). Petroselenic acid was the major fatty acid at all stages.