Objectives: A simple and rapid gas chromatography (GC) method with mass spectrometry (MS) detection was developed for the identification and quantification of anabolic steroids in pharmaceutical preparations from the black market. Material and Methods: After a liquid-liquid extraction of pharmaceutical products at acidic, neutral and basic pH with chloroform-isopropanol (9:1, v/v), the different steroids were separated by fused silica capillary column and detected by electron impact (EI)-MS in positive ionization mode. Results and Conclusion: The assay was validated in the range from 10 mg to 250 mg/g powder preparations and mg to 200 mg/mL liquid preparations with good determination coefficients () for the calibration curves. At three concentrations spanning the linear dynamic ranges of the calibration curves, mean recoveries were always higher than 90% and intra-assay and inter-assay precision and accuracy were always better than 15%. This method was successfully applied to the analysis of 15 pharmaceutical preparations sold by illegal sources. In only two cases the content was the one reported on the labels. In the other cases, no substances at all, or steroids different from those reported on the labels or different amounts from those declared were found.