OF THE ESTIMATED 50 MILLION NEW CASES OF VIRAL HEPATITIS INFECTIONS diagnosed annually,75% occur in Asia, where viral hepatitis is the leading cause of cirrhosis and hepatocellular carcinoma (HCC) (1). In Thailand, viral hepatitis is hyperendemic and thus an important public health problem. The attempt to control viral hepatitis B by mass vaccination has been set as a national (Expanded Program on Immunization (EPI) since 1992 and has resulted in the dramatic decrease of the hepatitis B carrier rate from 30% to 0–5% at the present (2,3). However, the other viral hepatitis infections, especially hepatitis C virus (HCV), are still prevalent. Presently, the prevalence of the hepatitis C carrier is very high, about 5%, or 3.5 million of the total 63 million Thai population. Poverty and poor hygiene are important contributing factors in the infection (4,5). In Thailand, the population is multiethnic. However, many epidemiological studies on HCV have focused on blood donors with Thai and/or Chinese ethnic backgrounds. Available information on HCV infections among ethnic minorities in Thailand is limited. Apart from the general rural population, the minority group of the hilltribers—who settle in northern Thailand, Myanmar, and southern China—can be considered an underprivileged group with respect to primary health care. Here we present a small-scale seroepidemiological report of the results of screening tests for anti-HCV in the hilltribers in a rural district near the Thai–Myanmar border, in the Northern region of Thailand. The setting of this study is Mae Jam District, Chiangmai Province, about 800 km north of Bangkok, the capital city. This district is a rural area near Myanmar where a number of hilltribers settle. The data from 200 hilltribers who received the hepatitis C screening test during year 2000 were reviewed. All laboratory tests were performed by medical technologists using a commercial immunological hepatitis C kit (Hepatitis C, Bhat-Biotec). Of the total 200 subjects, 86 were males and 114 were females. Seropositivity was detected in 15 cases, giving 1 total infection rate equal to 7.5% (Table 1). The rates in males and females were 9.3% (8/86) and 6.1% (7/114), respectively. The infection rate in males is not significantly higher than in females (p . 0.05, proportional Z test). The peak prevalence was found in the age group of 30–50 years old. Of interest is the fact that our setting, due its international borders with Myanmar, has a large number of hilltribers; a number of tropical infections among this population can be found. According to our study, a high prevalence of anti-HCV seropositivity (up to 7.5%) in this population was detected. This rate is about five times higher (p , 0.05, proportional Z test) than in the epidemiology survey among general Thais (1.4%) (6). Our findings are similar to the recent study of Ishida (7), which indicated as high as a 8.5% anti-HCV seropositivity rate among the local ethnic tribers in the same region. However, there are some differences, such as no gender differences in the prevalence in our study. Since this population may carry the disease and transmit it to other populations, effective screening for