Effectiveness of flubendazole, a newly introduced as an anthelmintic in Korea, was evaluated in 28 ascariasis, 28 whipworm infections and 17 pinworm infections in primary school children. All patients were orally given by flubendazole of 500 mg once. Stools for roundworm and whipworm and anal swabs for pinworm infections were examined both before and 25 days after treatment. After flubendazole treatment, all ascariasis and pinworm infected cases were cured. On the other hand, in whipworm infections, the cure rate was 82.1 percent (23 cured of 28 infected), and the egg reduction rate was 67.1 percent, respectively. Headache (one case), dizziness (2 cases) and abdominal pain (3 cases) were noticed as untoward effects, but they were mild and disappeared within 24 hours. These results demonstrate the excellent effectiveness of flubendazole in treating these helminth infections.