A disulphate fraction of the steroids in the urine of pregnant females was separated by chromatography on Sephadex LH-20. The steroids in this fraction showed the mobility of steroid disulphates on thin-layer chromatography, paper chromatography and high-voltage paper electrophoresis. After solvolysis, the free steroids were fractionated on silicic acid and by thin-layer chromatography. Fractions containing dihydroxylated C19 and C21 steroids were obtained. Using gas-liquid chromatography and gas chromatography-mass spectrometry, the following 18 steroids were identified in the disulphate fraction of neutral steroids in late-pregnancy urine: 5α-androstane-3α,17α-diol, androst-5-ene-3β,17α-diol, androst-5-ene-3β,17β-diol, 18-hydroxyandrosterone, 17α-hydroxydehydroepiandrosterone, 16β - hydroxydehydroepiandrosterone, 3β,17β-dihydroxyandrost-5-en-16-one, 5α-pregnane-3α,20α-diol, 5α-pregnane-3β,20α-diol, 5β-pregnane-3α,20α-diol, 5β-pregnane-3β,20α-diol, pregn-5-ene-3β,20α-diol, 3β,16α-dihydroxy-5α-pregnan-20-one, 16α-hydroxypregnenolone, 3α,21-dihydroxy-5α-pregnan-20-one, 3β,21-dihydroxy-5α-pregnan-20-one, 3α,21-dihydroxy-5β-pregnan-20-one and 21-hydroxypregnenolone. 5α-Pregnane-3β,20α-diol was the most abundant steroid in the fraction analysed, and preliminary quantitative data suggest that sulphate-conjugated pregnanediols and 21-hydroxypregnanolones are excreted mainly as disulphates in late pregnancy urine. The origin of these maternal urinary steroids is discussed.