Abstract: The present invention provides a process for the production of erythropoietin (EPO) with high purity and with a desired profile of EPO glycol-isoforms by using a combination of specific chromatographic steps in such a manner that the starting EPO glycol-isoform profile is changed or modified. The applied chromatographic steps includes at least (a) dye affinity chromatography, and (b) hydrophobic chromatography and/or (c) anion-exchange chromatography. In a preferred embodiment, the process further includes (d) gel filtration chromatography. The present invention also provides a process for the determination of erythropoietin (EPO) glycol-isoform profile in an EPO containing composition.