Summary A method was studied for the gaschromatogniphic separation and determination of 11-deoxy-17-ketosteroids. After enzymatic hydrolysis and solvolysis the urinary extract was purified by chromatography on a column of alumina. The steroids were converted to their trimethylsilyl ethers and separated by gas chromatography on a XE 60 2 % or a XE 60 0,60 % and SE 30 0,35 % column. The results found for dehydroepiandrosterone after different ways of hydrolysis with gaschromatography or the colorimetric Pettenkofer reaction were compared.