We report a case of wheeze in a heart transplant patient who was receiving chemotherapy for a transplant-associated lymphoma. The patient was in severe respiratory distress; there were no radiological abnormalities. A diagnosis of invasive bronchopulmonary aspergillosis was made by bronchoscopy and bronchoalveolar lavage. Despite prompt antifungal therapy the patient died. Wheeze in a non-asthmatic immunocompromised patient, even in the absence of radiological abnormalities, is highly suggestive of invasive bronchopulmonary aspergillosis. Diagnosis is best established by bronchoscopy and examination of the fluid obtained by bronchoalveolar lavage; currently the response to treatment is often disappointing.