The results are presented of albendazole trials on human taeniasis infections in Honduras, involving 56 of 68 individuals (2% of the inhabitants) found to be infected during surveys conducted in 15 rural communities. Of the 3 methods used for diagnosis of infection, the Kato cellophane thick smear showed 80% reliability, a combination of Kato and 'Scotch' tape perianal swab 88%, and clinical history of proglottid expulsion less than 50%. Individuals were treated with a dose of 400 mg of albendazole per day for 3 d, followed for 5 d to verify tapeworm expulsion, and evaluated again at 60 and 90 d to assess drug efficacy. All 56 treated individuals remained stool-negative after 60 and 90 d; a partial strobila or segments were recovered from 21 of them (37.5%). Of these, Taenia saginata was identified from 4, and T. solium from 15; 2 specimens could not be specifically identified. Based on negative stool examinations and clinical history after 60 and 90 d, albendazole seems to be a well tolerated, very effective drug for treating infections with Taenia spp. However, confirmation of these results is needed due to the difficulty of making a reliable diagnosis of such infections.