The phenomenon of abnormal pulmonary arteriovenous connections in patients with acquired lung disease rarely has been reported. We report three patients with acquired lung disease and hypoxia that did not respond to the administration of 100 percent oxygen. Contrast-material-enhanced echocardiography demonstrated intrapulmonary right-to-left shunting in all three patients. These cases suggest that patients with hypoxia due to acquired lung disease may he screened by contrast-enhanced echocardiography to identify the presence and the location of anatomic right-to-left shunts.