The efficacy of albendazole (400 mg taken once), mebendazole (100 mg taken once), and metronidazole (0.5 g thrice daily for 7 days) was evaluated when treating ascariasis, enterobiosis, and blastocystosis, respectively, in patients with HIV infection and in those with pulmonary tuberculosis. Metronidazole-resistant lambliasis was treated with exdisten (5 mg four times for 10 days) in 30.4% of the patients with HIV infection and in 43.3% of those with tuberculosis. Most HIV infected patients received antiretroviral therapy (ARVT). All the tuberculosis patients took isoniazid, ethambutol, pyrazinamide, rifampicin, and streptomycin. Efficiency was monitored by triple coproscopy at an interval of 5-7 days and by additional examinations using the method of Ritchii et al. There was parasitological cure (decreased infection rate for blastocystosis) and clinical improvement as positive changes in symptoms, such as nausea, weakness, headache, weight loss, and others, in all the patients with concomitant ascariasis, enterobiosis, and lambliasis. ARVT and antituberculosis drugs were observed to be better tolerated in all cases.