We report a case of Bardet-Biedl syndrome.A nine-year-old boy was having problems of recent loss of vision when in the dark. He was born with polydactyly in the feet for which he had surgery performed when he was seven weeks old. Mental retardation was significant and his vision was poor. Clinical and electrophysiologic examinations showed the existence of a pale optic disc and loss of the electroretinographic response under scotopic and photopic conditions.Based on the history, presentation, ophthalmic clinical examination, obesity, mental retardation and dental alterations, the patient was diagnosed with Bardet-Biedl syndrome. Current references are reviewed.