Abstract: Cortisone, hydrocortisone, prednisone, prednisolone, dexamethasone and betamethasone could be separated by HPLC on a 15-cm Hypersil (5 µm) column with methanol - 1,2-dichloroethane (3:197) as mobile phase (1.0 mL min-1). Each compound gave a response in a BAS LC4A electrochemical system, incorporating a mercury-coated gold electrode at -1.75 V, when 0.1 M tetrabutylammonium tetrafluoroborate (I) was added to the solvent as carrier electrolyte; calibration graphs were rectilinear and the sensitivity was 200 ng per injection. However, none of the steroids was retained on the column in the presence of I. The method should be applicable in flow injection analysis, or with post-column addition of electrolyte.