In order to settle the precise spectrum of activity of albendazole, its efficacy was tested in the treatment of Strongyloides venezuelensis in experimentally-infected rats. The results were compared to those obtained with two other benzimidaloze derivatives, cambendazole and mebendazole. The three compounds were shown to be effective in eradicating intestinal adult worms completely, when single doses of 625, 12.5, 25 of 50 mg/kg were used. However when smaller doses were employed (5 mg/kg) worm burdens were reduced in 87%, 98% and 80% by albendazole, cambendazole and mebendazole respectively.