Hand clasping and arm folding probably depend on genetic factors. No simple Mendelian mechanism could be found to explain the findings but some relative factors have been found on the frequencies of the types of hand clasping and arm folding. The data obtained in patients at 2 tuberculosis hospitals seem to show that the main general findings observed in healthy individuals from different populations hold true for tuberculosis patients. The data here presented refer to 540 patients of one hospital for leprosy in Bauru City, SP (Sanatorio Aimores). The results are presented, with a calculation of the frequencies of the types of hand clasping and arm folding according to sex, age and ethnic group in the subjects under investigation.