We report the case of a 77-Year-old immunocompetent woman who required intensive care for acute dyspnea revealing complete atelectasia of the left lung related to an aspergillus mycelium plug blocking the principal bronchus. The clinical course was favorable after deobstruction by thermocoagulation and oral itraconazole given for six Months. The patient was free of parenchymatous or endobronchial sequelae. Adjuvant oral corticoid therapy was given temporarily during the second Month of treatment when signs of transition towards allergic aspergillosis developed. Four Months after discontinuing the antifungal treatment, the patient developed a new episode of acute dyspnea caused by atelectasia limited to the right lower lobe. Treatment by itraconazole was resumed and continued as long-term therapy. No recurrence has been observed for eighteen Months. The diagnostic and therapeutic problems raised by Aspergillus fumigatus are well known in the immunocompromised subject, but can also be encountered in the immunocompetent subject.