Daily saunas taken by a young man were followed by fever, chills, malaise, dyspnea, cough, and myalgia from six to eight hours later. Symptoms, which were related to pouring water from a sauna bucket over the heating element, progressed to chronic dyspnea and fatigue. Serial serum samples showed precipitin reactions to bucket water and extracts of bucket mold. IgG antibody activity, demonstrated by radioimmunoassay, suggested that Pullularia was a major antigen.