The photographic developing agents, Metol and hydroquinone in a photographic developer, were analyzed directly by means of liquid chromatography without any pre-treatment of the developer. The eluent of the anion exchange chromatography was prepared by eliminating the developing agents from the developer. The oxidation products of these developing agents, which were exhausted by air or film processing, were also determined. These substances were identified by the retention time of the chromatogram and spectral absorbance of eluated peak solution. It showed that hydroquinone was preferentially oxidized in a mixture of Metol and hydroquinone, either during development or by reaction with oxygen.