The percentage contents of oil and protein in the seeds of 17 species belonging to 9 genera of the Sterculiaceae family, growing in Madagascar, were determined. The major fatty acids were palmitic (11.6-27.5%), oleic (8.3-32.6%), linoleic (4.2-45.8% ), malvalic (tr-53.7961, and sterculic (1.3-24.876) acids. Heritiera littoralis seed oil was characterized by a high content of malvalic (53.7 %) and sterculic acids (12.4 % ). Cyclopropene fatty acids were identified and determined by using a combination of gas chromatographic and 'H and 13C NMR analyses. Dihydrosterculic acid was also detected in all samples at a low concentration.