The 1 ipid extract prepared from the bark of the West African Petersia africana was found to contain arachidonic compound (C.20:4) in substantial amount. The pure compound after isolation by preparative gas­liquid chromatography (glc) was identified by both physical and chemical methods. In addition other fatty acids linoleic (C 18:2), oleic (C 18:1), palmitoleic (C 16:1) myristoleic (C 14:1) lauroleic (C 12:1) were also found. The lipid fraction proved to contain triacylglycerol, cholesterol ester, hydrocarbons and glycosides. This is the first report of the detec­tion of arachidonic compound in P.africana.