The main idea of Sasang medicine is that everyone has his own unique constitution. There are four kinds of constitutions and these are Taeyang, Soyang, Teaum and Soum. Although Sasang medicine is a unique and originative medical theory with creative ideas of Korean traditional medicine, the classification of individual constitution mainly depends on the methods which may not be objectively proven and scientifically understood. This study was carried out tn establish scientific understanding of Sasang medicine by investigating the possible genetic difference among four constitutions. Sasang constitution classification was performed by Sasang medicine research group in Korea Institute of Oriental Medicine and Kyung Hee University, Genomic DNA was prepared from the blood of individuals of different constitutions and RAPD(Random amplified polymorphic DNAs) analysis was then carried out to investigate the possible difference among different constitutions on DNA level. For RAPD analysis, ten different random primers were applied to Teaum, Soyang and Soum group DNA samples and the presence of DNA markers specific for each constitution was investigated.