A case of unilateral pigmentary degeneration of the retina was followed up over a period of 36 years. Clinical and electrophysiological findings of the affected eye resemble those of retinitis pigmentosa. The fellow eye is normal. The family history is negative. Therefore, the diagnosis of unilateral retinitis pigmentosa is not beyond dispute. Regardless of the long observation period the existence of unilateral pigmentosa could not be proven.