The pulmonary scintigraphic findings from 4 patients with fibrosing mediastinitis due to histoplasmosis are reported. The ventilation/perfusion (V/Q) mismatch mimicked pulmonary emboli. In these cases the chest radiographs and/or 67Ga scintigraphy were abnormal, suggesting mediastinal or hilar disease. Awareness of the nonembolic conditions that can result in V/Q mismatches is important in the interpretation of lung scans.