The author reports a case of congenital somatic hemi-hypertrophy, the first in Brasilian medical literature. The author agrees with the view that this process depends on disorders of the normal activity of the autonomic nervous system. The patient has been studied according to the technique of Gesell and Amatruda's test of development. The child's degree of development was found to be normal, and it is remarkable that his motor quotient can be taken as higher than the standards for normal children. The author stresses the importance of the correct determination of the psychomotor development in such cases; this test is the only dependable point to safely state a prognosis.
