Hyalinosis cutis et mucosae (lipoid proteinosis, Urbach-Wiethe disease) is a rare syndrome with autosomal recessive inheritance. The disease is characterized by diffuse deposition of a hyaline-like substance in the dermis, the submucosal connective tissue and various internal organs. The oral mucosa of affected people becomes nodular and thickened, with primary involvement of the labial, buccal and palatal mucosa, posterior tongue, and lingual frenulum. We report the case of a 66-year-old man with hyalinosis cutis et mucosae who presented with gingival hyperplasia due to diffuse deposition of hyaline-like material, and discuss the diagnostic significance of the microscopic findings of the gingival tissues. The present clinical features are also compared to those of the same patient at the age of 38 years.