A case of a 71-year-old woman showing pigmentary degeneration of the retina associated with posterior subcapsular cataract in one eye, with a normal fellow eye, is presented. Clinical examinations of the patient were performed in order to rule out the various causes which are known to produce funduscopic features that mimic retinitis pigmentosa. Since these investigations were all negative, the fundus changes were interpreted as a unilateral retinitis pigmentosa. One year later, the patient was re-examined and an exfoliation syndrome was discovered in the affected eye, while the fellow eye was unchanged. An association of unilateral retinitis pigmentosa and exfoliation syndrome in the same eye can be regarded as exceptional. The possibility of a correlation of the pathogenetic mechanisms involved in the development of both conditions is discussed.