A 88 year old Japanese male was repeatedly infected with Ancyclostoma duodenale. He underwent an artificial anus operation about 55 years ago. He appeared to be infected with hookworm earlier than in 1977 and developed severe anemia. Though he was treated with pyrantel pamoate and mebendazole several times, reinfections developed in each time. A possible origin for his reinfections was his own feces defecated through his artificial anus. Unsanitary handling of the anus and the feces exposed himself to oral or percutaneous infection. Besides, a single dose of pyrantel pamoate, usually very effective against Ancylostoma duodenale, was not so effective in this patient. Therefore, we prescribed multiple doses of pyrantel pamoate, and followed by a single dose of mebendazole. However, reinfections still persisted because of his unsanitary behavior.