Following i.v. administration of [4-14C]cortisol, various sulfate conjugated metabolites of cortisol in urine were identified and their respective excretion rates measured. The results obtained demonstrated the following: 1) sulfate conjugates as a group are excreted considerably slower than glucuronide conjugates; 2) sulfate conjugates of steroids with non-reduced ring-A (C-21 sulfates) are excreted (and presumably formed) much faster than steroid-3-sulfates, which require reduction of the ring-A prior to the conjugation; 3) the excretion of C-3 sulfates of ring-A reduced steroids with glycerol side-chain (cortols and cortolones) is significantly faster than those of the corresponding steroids with dihydroxyacetone side-chain (THF, THE and their 5alpha-isomers); 4) the relative concentrations of C-21 sulfates of steroids with ring-A intact (FK, EK, ER, epiER and 6beta-hydroxycortisol) are much higher than the concentrations of C-21 glucuronides of these steroids.