The determination of nandrolone and its major metabolites in urine of a healthy volunteer is typically performed by fused-silica capillary column gas chromatography with electron impact quadropole mass spectrometry. Two well-known urinary metabolites of nandrolone, 19-norandrosterone and 19-norethiocholanolone, were isolated by XAD-2 adsorption from urine, eluted with methanol and separated into unconjugated and conjugated fractions. The conjugated fraction was hydrolyzed with beta-glucuronidase from Escherichia coli and the samples derivatized with MSTFA/ammonium iodide/dithioerythritol. Ion fragmentograms of the bis-trimethylsilyl derivatives of nandrolone and its metabolites displayed molecular ions of M+ = 420 and M(+) -15 = 405. Extraction yield and the minimum detection limit of nandrolone in urine were identified. Finally, excretion rates of nandrolone and its metabolites in urine were determined.