Abstract: A GC/MS procedure described in this paper was applied to study the metabolism ofmibolerone in human urine Mibolerone and its six metabolites were detected in the excretion study urine. All detected metabolites of mibolerone were confirmed structurallyfirst time. The excretion curve showed that in urine mibolerone was excreted mainly asparent form I and 5β-4H metabolite Ⅵ in cunjugation.