Albendazole, a new broad spectrum anthelmintic drug, was evaluated for anthelmintic effects in 74 patients with single or mixed infections of Ascaris lumbricoides, Trichuris trichiura. Enterobius vermicularis, Metagonimus yokogawai, Clonorchis sinensis and Taenia spp. Albendazole was administered as a single dose of 400 mg. The cure rate for A. lumbricoides and E. vermicularis was 91.4% and 98.1% respectively at day 30 post-treatment: for T. trichiura it was 51.1% and for M. yakogawai and C. sinensis it was 33.3% and 13.3% respectively. The egg reduction rate at day 30 was 98.5% in A. lumbricoides, 76.5% for T. trichiura : 60.0% for M. yokogawai and 59.6% for C. sinensis However it was not cured in all 5 cases of taeniasis at three months follow-up examination. On the other hand, the various dosages of albendazole were given to the patients infected with C. sinensis and Taenia spp. respectively. The follow-up examinations were carried out at 30 days after treatment in clonorchiasis and at 3 months after treatment in taeniasis. In the results, the recommended dosage of albendazole for clonorchiasis is $3{ imes}400mg$ for 3 consecutive days and for taeniasis $2{ imes}400mg$ for 3 consecutive days. There were no side effects with the above dosages except only a mild abdominal pain and dizziness in a few patients. Albendazole appears to be more effective than the other available broad spectrum anthelmintic drugs.