Congenital radio-ulnar synostosis is a rare condition with approximately 350 cases reported in the literature. The condition is due to the failure of segmentation between the radius and ulna. The rarity of the condition often leads to delayed clinical diagnosis. Average age at diagnosis is 6 years, and ranges from 6 months to 22 years. The sexes are affected 3-2 male/female and 60% of cases are bilateral. Functional deficits with congenital radio-ulnar synostosis depend on the severity of the deformity and on whether or not it is bilateral. The disability is most significant in bilateral cases with severe pronation. Children initially may have reduced radial heads and later develop symptomatic radial head subluxation as adolescents. Therefore, they must be followed-up radiographically. Indications for surgery still remain somewhat controversial but are related to bilaterality and the degree of deformity.