The ring A monoglucuronides and monosulfates of 2-hydroxyestriol were synthesized from 2-hydroxyestriol 16,17-diacetate by means of the Koenigs-Knorr reaction with methyl alpha-acetobromoglucuronate and sulfation with sulfur trioxide-pyridine complex, respectively. The conjugated positions of these compounds were definitely established by conversion to 2-hydroxyestriol monomethyl ethers by methylation, then enzymatic hydrolysis. The ring D monoglucuronides and monosulfates of 2-hydroxyestriol were also prepared from 2-hydroxyestriol 2,3-dibenzyl ether by glucuronidation and sulfation in a similar fashion followed by debenzylation, respectively. The positions of conjugation were established on the basis of their 1H-nuclear magnetic resonance spectral data.