Mongolia is known for its high endemicity for viral hepatitis. Previous studies report that the seroprevalence of hepatitis B virus (HBV) is 11.8% (178/1,512) among the unvaccinated population in 13 provinces and Ulaanbaatar city. The serosurvey of adults (>20 years of age) conducted during 2013 among persons in four provinces and in Ulaanbaatar showed that the overall prevalence of hepatitis B surface antigen (HBsAg) positivity was 10.6%. The overall prevalence of anti-hepatitis C virus (HCV) and HCV ribonucleic acid among 1,512 apparently healthy subjects was 15.6% (236/1,512) and 11.0% (167/1,512) respectively. In a previous study, we reported on the prevalence of HBV, HDV, and HCV infections in 110 consecutive patients presenting with acute hepatitis at eight city hospitals in Ulaanbaatar. In that study, 16.4, 32.7, 6.4, 1.8, and 27.3% of the patients were diagnosed as having acute hepatitis due to hepatitis A, B, C, HBV/HDV coinfection, and superinfection respectively. In the current study (2012-2014), results show that acute hepatitis A, B, C, and D was diagnosed in 47.9, 40.7, 5.3, and 9% respectively. Chronic HBV and HCV infections, which are associated with cancer and cirrhosis respectively, are responsible for 95% of liver cancers in Mongolia. The most common etiology for hepatocellular carcinoma was HCV infection (n = 89, 45.6%), followed by HBV infection (n = 67, 34.4%). How to cite this article: Baatarkhuu O, Uugantsetseg G, Munkh-Orshikh D, Naranzul N, Badamjav S, Tserendagva D, Amarsanaa J, Young KD. Viral Hepatitis and Liver Diseases in Mongolia. Euroasian J Hepato-Gastroenterol 2017;7(1):68-72.