The presence of lipids in nucleoli of roots ofVicia fabahave been confirmed in two ways, namely, (i) by cytochemical studies of sections from fixed and embedded roots, and of unfixed and fixed frozen sections, and (ii) by autoradiographic studies on the incorporation of ethan-l-ol-2-amine-2-14C hydrochloride and14C-choline chloride. These lipids appear to be, in part, phospholipids.