The effect of therapy on the clinical course of pleuropulmonary and systemic Nocardia asteroides disease in 78 reported cases was analyzed. All patients were treated with drugs. In 72 cases sulfonamides alone or in combination with other antibiotics was given; 45 patients underwent surgical procedures. The extent of disease had a bearing on survival as only 3 of 39 patients (7.6%) with isolated pleuropulmonary involvement died. These fatalities occurred among the 16 patients of this group who received immunosuppressive drugs. One of 12 patients (8.3%) with suppurative foci other than brain abscess and pleuropulmonary nocardiosis died, whereas the fatality rate of cases with nocardial brain abscess was 47.8%. Thirty-one patients relapsed or had progression of disease while receiving drugs for nocardiosis, 30 of them within the first three months. Prolonged post-treatment observation is essential in the management of nocardiosis as four patients relapsed after drug therapy was discountinued, three of them between six and eight months. Although there was no significant difference in the survival of patients treated with only drugs when compared to those who also had surgery, no fatalities occurred among those medically treated for six months or longer (p = .0091).