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We recently purified two closely related 33 kDa proteins from rat hepatic cytosol, designated bile acid binder I and II, which selectively bind bile acids with comparable affinity as glutathione S‐transferase B. This work has now been extended to human liver in which we have identified a similar cytosolic binding activity in the 30–40 kDa fraction from gel filtration. Subsequent chromatofocusing and hydroxyapatite chromatography resulted in the isolation of a homogenous monomeric protein of 36 kDa. The binding affinity of this protein for lithocholate using the displacement of 1‐anilino‐8‐naphthalenesulfonate (ANS) was 0.1 μM, whereas human hepatic glutathione S‐transferases purified from glutathione affinity chromatography demonstrated no competitive displacement of ANS.