From magnetic susceptibility measurements the J-vaIue of (mu-hydroxo)bis[pentaamminechromium(III)] chloride hydrate was found to be 32.3 cm(-1). The EPR spectra of the complex diluted in the analogous cobalt(III) complex have been recorded down to 4 K, The spectrum from the quintet state has been identified by the temperature variation of the intensity, Below 200 K the quintet spectra consist of two spectra originating from two different sites in the crystal, Both spectra have been computer simulated, and the following two parameter sets were obtained for the two different ions in the crystal : D-e = -0.0512(1) cm(-1), E-e = -0.026361) cm(-1); D-e = -0.0498 cm(-1), E-e = -0.0263 cm(-1).