Prior to this report, pigmentary degeneration of the retina had been described in four of the six types of mucopolysaccharidosis (MPS). However, it had not been described in Morquio's syndrome. To the authors' knowledge, the case presented represents the first patient with Morquio's syndrome demonstrating ophthalmoscopic and electrophysiologic abnormalities. The patient demonstrated arteriolar narrowing, as well as an increased photopic b-wave implicit time, decreased scotopic b-wave amplitude, and a slightly abnormal electro-oculogram (EOG). At 43 years of age, this patient represents the oldest individual with Morquio's syndrome tested electrophysiologically. It is proposed that the retinal involvement in the disease is mild but progressive and therefore perhaps is not seen in younger patients but becomes apparent in older persons with Morquio's syndrome.