Abstract: The paper reports the investigation on human intestinal nematodes in Qinghai Province during 1988-1990. Stool specimens of 16 079 persons from 32 spots were examined by mo dified Kato Katz method and larva cultivation method. Among the people examined, 5 482 were positive, the overall infection rate being 43.1%. Five species of nematode were detec ted. The infection rates of Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis (Children under 12 years old), Trichostrongylus orientalis and Strongyloides stercoralis were 33.9%, 0.6%, 20.6%, 0.08%, and 0.02%, respectively. Significant differences in infection rates were revealed between different groups when statistical analysis was made on the ground of age, sex, nationality or occupation. The survey provide scientific data for the prevention and treatment of intestinal parasites in the province.