A case is described of a newborn, admitted to hospital because of severe salt loss at the age of 1 month. Subsequent analysis of urinary steroid excretion, by gas chromatography and gas chromatography-mass spectrometry, revealed that the patient suffered from pseudohypoaldosteronism. However, it was difficult to interpret the results unambiguously, since the first urinary analysis appeared to suggest 21-hydroxylase- or 18-hydroxylase deficiency. The final diagnosis was possible only after detecting high urinary levels of aldosterone and tetrahydroaldosterone. It is concluded that neonatal urinary steroid profiles should be interpreted cautiously in order to arrive at the correct diagnosis.