A new case of trisomy of the distal third of the long arm of chromosome 10 due to familial translocation t(10;18) (q24;p11) is described. The main clinical and radiological signs may be summarized as follows: growth at lower limits of normal; poor facial expression; round, flat face with high, broad forehead, fine, highly arched eyebrows, pseudohyperthelorism, microphthalmia, flat, broad bridged nose, hypoplasia of the bony structures of the central area of the face, "fish mouth", macroglossia, micrognathia; short neck; marked dextroconvex lumbar scoliosis; psychomotor delay of mild degree; selective, more pronounced speech delay. Our observation confirms the suggestion by Yunis and Sanchez that a clinical syndrome corresponds to this chromosomal alteration. However, some interesting differences from the previously reported cases, i.e., the absence of microcephaly and of severe impairment of growth and psychomotor development induce us to establish a more favorable prognosis in our case.