The relationship between continuing benefits from spa therapy to maintenance therapy (swimming training in a hot spring or hot water pool one to three times per week) and environmental factors was examined by a questionnaire sent to 60 patieints with bronchial asthma. The subjects had been patients at Misasa Branch Hospital and received spa therapy for one to three months. The efficacy rate of spa therapy ranged from 78 to 81%. In patients receiving maintenance therapy after discharge, continuing benefits from spa therapy were ovserbed for one year following therapy at our hospital, although the efficacy rate decreased as their environment worsened (air pollution). However, in patients with maintenance therapy, the influence of environmental factors was considerably less. In contrast, continuing benefits from spa therapy were very low in patients who did not receive maintenance therapy after discharge from our hospital. Continuing benefits were particularly diminishie in those living with air pollution. These results show that the continuing benefit of spa therapy on bronchial asthma is affected by maintenance therapy and environmental factors.