Abstract: Local inhabitants in 8 towns/townships of the counties Yushu, Zhiduo and Chengduo were examined with serology and ultrasound in 2006. Among 2 251 people tested by indirect hemagglutination （IHA）, 207 showed anti-hydatid IgG positive （9.2%）. Ultrasound examination found 106 cases out of 2 581 people, with a morbidity of 4.1%. Females showed higher sero-positive rate （11.3%） and morbidity rate （5.0%） than males （6.6% and 3.0% respectively）. The highest sero-positive rate was in the group of 40-49 years old （16.4%）. The morbidity rate increased with age, with the highest rate （15.5%） in the group of 60 years old and above. Occupationally, those involved in semi-agriculture and semi-animal husbandry showed highest sero-positive rate and morbidity rate, 21.5% and 11.4% respectively. The survey demonstrated that the prevalence of hydatid disease in human population is at a high level in Yushu Tibetan Autonomous Prefecture.

Key words: Hydatid disease, Prevalence, Tibetan, Qinghai