Twenty-four of 230 patients with patent ductus arteriosus had hypovascularity and hyperlucency in the left lung on preoperative chest roentgenograms. Two of the 24 patients died shortly after operation, and one was unavailable for follow-up. During the postoperative course (mean, three years), roentgenograms of eight of the remaining 21 patients showed persistent, unequal pulmonary vascularity and hyperlucent left lung, with no evidence of air trapping, and two patients had diminished volume of the hyperlucent left lung compared with that of the right lung.