When golden hamsters infected with adult Necator americanus were treated ig with albendazole(Alb) 75 or 150 mg/kg, the efficacy rates were 83.8% and 100%, respectively. Three days before treatment, the mean numbers of larvae recorded from the incubation of feces from 2 treated groups were 29,716 +/- 3,299 and 28,256 +/- 118 per gram of feces, while in the control group, it was 8,828 +/- 2,659. Within 3 days after treatment, no larva was detected in the 2 treated groups, but in the control group the mean larva number was 9,066 +/- 7,416. Furthermore, in 2 treated groups none or only a few degenerated eggs could be found using saturated saline solution method. when infected golden hamsters were treated ig with Alb at a single dose of 150 or 300 mg/kg on day 3, 7 or 14 after infection with the third stage larvae, the egg positive rates in the feces were 0-9.1%, while the worm reduction rates were 96.8-100%.