A controlled prospective study was undertaken to compare the efficacy and benefits of home and hospital treatment for patients with exacerbations of pulmonary disease caused by cystic fibrosis. A total of 41 home and 41 hospital treatments were analyzed. Home and hospital patients were matched according to sex, age, pulmonary function tests, and arterial blood gas values. Both home and hospital treatments resulted in statistically significant improvement in pulmonary function. A comparison of these values did not show any statistically significant difference between groups at admission or discharge. Furthermore, the mean number of treatment days for both groups, individually determined by the primary physician, was equivalent (home 17.7 +/- 1.1 days, hospital 18.1 +/- 4.1). The mean charge for a home treatment was approximately $10,000, and for a hospital treatment $18,000. Sixty-five percent of home care patients and 68% of hospital patients required retreatment for pulmonary exacerbations within the study period; the interval between pulmonary exacerbations for the two groups was not significantly different. In addition, 85% of patients receiving treatment at home were able to maintain at least some of their school or work activities. These data indicate that home therapy for cystic fibrosis patients with pulmonary exacerbations is less costly and is as effective as in-hospital therapy.