This retrospective study was conducted to verify the possibility of a relationship between morphological somatotypes and Adolescent Idiopathic Scoliosis (AIS). The sample was composed of 77 adolescent girls presenting Idiopathic Scoliosis. In every case, scoliosis was important enough to necessitate a corrective surgery. The control group (historical type) was taken from an anthropometric study done in 1990 [5]. Morphotypes were evaluated from medical slides with pre-established criteria based on Sheldon's technique [3, 4]. Three somatotype values were obtained: One for ectomorphism, a second for mesomorphism and a third for endomorphism. This classification system is calibrated in a way that the summation of these 3 values necessarily gives 7. AIS patients appear less mesomorphic with a mean value of 1,208 +/- 1.03 than the control group with a mean value of 1,923 +/- 0.89 (Student "t" test: 6,149, p < 0.0001). Based on these results, a relationship between morphological somatotypes and the presence of AIS appears possible. A more elaborate prospective study will be needed to support this hypothesis.