Objectives This study aimed to examine differences in the hepatic function disorders and prevalence rates of liver diseases in accordance with the Sasang constitutional type, and to analyze whether Sasang constitution is a significant risk factor for fatty liver. Methods A total of 1211 patients who underwent health check-up at the Ilsan Hospital of Dongguk University and had their physical constitutions diagnosed by a specialist in Sasang constitutional medicine from October 31, 2011 to September 28, 2012 were used as the subjects of this study. Presence of hepatobiliary diseases was analyzed from the results of the hepatic function test, lipid test and viral hepatitis infection marker test in the biochemistry tests, and abdominal ultrasonography. Results & Conclusion Subjects of the study were composed of 691 males and 520 females and, in terms of Sasang constitution distribution, 550 Taeeumin, 343 Soeumin and 318 Soyangin. As the results of analysis of prevalence rates in accordance with Sasang constitutions, significant differences were observed in the prevalence rates of abnormal groups in the cases of AST, ALT, GGT, Triglyceride, HDL-cholesterol and LDL-cholesterol, and all of their prevalence rates were in the descending order of Taeeumin, Soyangin and Soeumin. Soeumin displayed significantly higher positive rate for HBs Ab in comparison to Taeeumin and Soyangin. In the results of abdominal ultrasonography, the prevalence rates of fatty liver displayed significant differences and were in the descending order of Taeeumin, Soyangin and Soeumin. And as the result of logistic regression analysis in order to find the risk factors of fatty liver, the Sasang constitution was found to be a significant risk factor for fatty liver. The odds ratio of Taeeumin in fatty liver was found to be 1.634 higher than Soeumin and 1.773 higher than Soyangin