Biologically active recombinant human follicle stimulating hormone (rhFSH) was produced in Chinese hamster ovary cells and purified by a series of chromatographic steps. The chromatographic steps included anion-exchange chromatography (DEAE Sepharose F/F, Q Sepharose F/F), hydrophobic interaction chromatography (Source 15 PHE), and hydroxyapatite chromatography (Macro-Prep ceramic hydroxyapatite type I). A distinctive step of the purification process developed was the use of ZnCl$_2$ for the removal of non-glycosylated or lowly-glycosylated FSH and impurities through co-precipitation with Zn$^{2+}$. Purified rhFSH was identified and characterized by several physicochemical and biological methods such as gel electrophoresis, high-performance liquid chromatography, amino acid analysis, carbohydrate analysis, and biological activity. The overall yield of the purification was ~$30\%$. The rhFSH preparation obtained showed high purity (>$99\%$) and high in vivo potency (>16,000 IU/mg). Carbohydrate analysis suggested that the purified rhFSH contained approximately $40\%$ (w/w) carbohydrate with di­or tri-antennary structure on average, which is somewhat more heavily sialylated than commercially available rhFSH. In conclusion, the results of these analyses established an identity of the purified rhFSH with natural FSH from human pituitary glands, and furthermore, the purified rhFSH preparation showed higher in vivo potency and was slightly more heavily sialylated than commercially available rhFSH.