Alkaptonuria is found relatively frequently in Slovakia, Eastern Czechoslovakia (1 in 25,000 inhabitants). Reported herein are the clinical, radiographic, and biochemical aspects and genetics of 126 patients with alkaptonuria. Forty-seven were diagnosed in childhood; the sequential appearance of each manifestation is documented by decade. A simple screening method for this disorder is described. Pedigree analyses confirm recessive inheritance. Possible genetic and sociologic factors responsible for this high frequency of alkaptonuria are discussed.