The authors undertake a comparative study with two broad-spectrum anthelmintics, benzimidazole derivatives - Albendazole and Mebendazole in the treatment of Ascaris lumbricoides, Necator americanus and Trichuris trichiura infections. The subjects of the trial were eighty-nine patients, forty-eight of them treated with Albendazole and forty-one with Mebendazole. Mebendazole was given orally, 100 mg. twice daily, for three consecutive days, and Albendazole in a single oral dose of 400 mg. Tolerance was uniformly excelent and no side-effects were reported. Statistical analysis of the performed study showed that Albendazole is asefficaciousas Mebendazole in the treatment of Ascaris lumbricoides, Necator americanus and Trichuris trichiura infections. The advantage of Albendazole is the single oral dosage. In patients not cured parasitologically, significant reduction of number of eggs per gram of stool was observed with both drugs.