A simple, rapid and reproducible procedure for fractionation of cytosoluble glycoproteins from calf brain has been developed. 1) The main steps of this procedure were ammonium sulphate fractionation and column chromatography on hydroxylapatite-cellulose gel, six well defined different subfractions being finally obtained. 2) Subfractions, I, II and III were the richest in carbohydrate (15-35 microgram/mg protein) and in N-acetylneuraminic acid; subfraction IV the poorest in carbohydrate; subfractions V and VI the richest in mannose; subfraction VI the richest in fucose. All subfractions contained glucose. The different subfractions had very similar aminoacid composition. The polyacrylamide gel electrophoresis profile of proteins and glycoproteins contained in the different subfractions was different and indicated a certain degree of heterogeneity. 3) The contamination by gangliosides of the first three subfractions was appreciably low and ranged within 1.5-6% (in terms of ganglioside bound NeuNac/glycoprotein bound NenNAC). Subfractions IV, V and VI, the poorest in protein linked carbohydrates, carried higher ganglioside contamination.