Classical purification of the glycoprotein equine chorionic gonadotropin (eCG) from serum includes pH fractionation with metaphosphoric acid, two ethanol precipitation steps as well as dialysis followed by fixed-bed chromatography. A simplified process requiring only 1/3 of the solvent and improving the yield from 53 to 65% has been developed. The process comprises an ultra-/diafiltration step after the first ethanol precipitation, directly followed by an adsorption/desorption procedure based on magnetic microadsorbents with N,N-diethyl-ammonium functionalization. The process reaches an overall purification factor of eCG of more than 1800 and an average product activity of 1300 IUELISA/mg. After adapting the parameters of the fractionation and the type of magnetic microadsorbents, the new concept is likely to be transferable to other serum proteins.