Seed oils of nine species of Cucurbitaceae were analyzed by gas chromatography and other techniques. The oil of Ecballiumelaterium yielded 22% of punicic acid; Cucumisdipsaceus and Cucurbitaficifolia had the ordinary palmitic–oleic–linoleic composition; a variety of Momordicacharantia had 57% of α-eleostearic acid. Occurrence of punicic acid as the major acid of Trichosanthesanguina was confirmed. No evidence could be found for the existence of an isomer of linoleic acid in Telfairiapedata oil. The fatty acid composition was determined quantitatively for the above oils and for those of Cucumismelo, Lagenariasiceraria, and Luffacylindrica. The 4-bromophenacyl esters of α-eleostearic and punicic acids were prepared.