Lavage limited to an isolated lobe was performed on multiple occasions using a cuffed fiberoptic bronchoscope in a patient with alveolar proteinosis. Sequential ventilation-perfusion scintiphotoscans were used to preselect and follow the functional behavior of the lavaged lobe. Lavage led to functional improvement. The technique of fiber-optic bronchoscopic lobar lavage is simple and may find application in patients in whom lavage of an entire lung may be hazardous.