The purpose of these work is to present and describe the reliable for sex determination in recent Thai population using metacarpal bones. A sample of bones corresponding to a Thai population deposited at the department of Anatomy, faculty of medicine Siriraj hospital, Mahidol University was analyzed. The sample consists of 25 - 80 years old adult individuals 30 Thai people (male = 18, female = 12). We also analyzed the existence of significant differences between the mean of both sexes for each of variables analyzed, applying the t-test statistic and discriminant analysis procedure of the SPSS software. Not only we found that the mean and standard deviation of the metacarpal bones in male are more than female but also there were significantly different between male and female (the best of determination is ECD in right second metacarpal bones). Moreover we found that ECD of the right second metacarpal bones is the best of determination in male (83.8%). However, we found that 91.7% of reliability in female (the best of determination is MLDM and APDDE in right second and fifth metacarpal bones respectively). The result suggest that metacarpals are the one choice that can be used for sex determination in forensic identifications.