Terminations of the main lines and the main-line indices were examined on the palm prints of 65 patients with 47, XXY Klinefelter's syndrome. No significant differences were observed between the patient and control groups as far as the termination frequency for each main line was concerned. A significant bimanual difference was noted for all the main lines among the controls, but not for main lines D and C in the patient group. Additionally, the bimanual difference of the main-line index was definitely of smaller magnitude in the Klinefelter's syndrom group than among the controls, indicating less asymmetry.