Homocystinuria due to cystathionine synthase deficiency is an autosomal recessive error of sulphur amino acid metabolism characterized clinically by lens dislocation, mental retardation, skeletal abnormalities and thromboembolic phenomena. We have evaluated roentgenologically our series of 12 pediatric homocystinuric patients to detect skeletal abnormalities. Bone changes are widespread and occur mainly in dorsolumbar spine and in epi-metaphyseal growth areas. Osteoporosis is the most important finding. Dolichostenomelia and arachnodactily are relatively common. Calcific spicules occur frequently in the wrist physes.