Cocaine inhalation is associated with multiple pulmonary complications including pulmonary infiltrates, pulmonary edema, barotrauma, tracheal injury, and alveolar hemorrhage. Little has been reported about ventilation/perfusion (V/Q) lung scanning in patients who smoke cocaine. The authors report a case of inhalation cocaine abuse mimicking pulmonary embolism by V/Q scan criteria. This case report documenting perfusion abnormalities within hours of cocaine smoking which resolved within days provides the first in vivo evidence for pulmonary vasoconstriction.