Until recently, rigid bronchoscopy was considered too risky for premature infants. We report a 658 g infant with life-threatening mediastinal shift due to right pulmonary atelectasis. Rigid bronchoscopy revealed tenacious mucous plugs in the right main bronchus. The collapsed lung was successfully reinflated after bronchial lavage with a rigid bronchoscope, with the help of intermittent high-frequency jet ventilation (HFJV). The infant's mediastinal shift was reversed and the vital signs became stable. In our experience, rigid bronchoscopy combined with HFJV is a valuable diagnostic and therapeutic procedure for very small premature infants.