In 1966, Mietens and Weber reported four out of six siblings from a consanguineous couple with growth failure, dislocation of the head of the radii, bilateral flexion contracture of the elbows, short ulnae and radii, bilateral corneal opacities, horizontal and rotational nystagmus, strabismus, small, pointed nose and mild to moderate mental retardation. Since then, only three other cases have been reported. We report on two new cases, a pair of female twins aged 9 years. The patients were born after an uneventful, normal pregnancy, to young and non-consanguineous parents. After birth, physical findings included horizontal nystagmus and dislocation of both elbows because of abnormally short radii and ulnae in both twins. Further clinical examinations showed moderate psychomotor delay with marked language compromise. Karyotypes were normal in both girls. A review of the literature reveals that the Mietens-Weber syndrome is an uncommon disorder with a probable autosomal recessive pattern of inheritance. To our best knowledge, including the two cases reported here, only nine cases have been observed so far. The finding of congenital nystagmus and radii dislocation in a patient with mental retardation is probably nonrandom and is highly suggestive of Mietens-Weber syndrome.