Sixty-six patients underwent various types of operative repair of a sternal wound breakdown. A study was performed to compare the spirometry values before and after these repairs to determine the long-term effect on respiratory function. Forty-four patients were tested postoperatively; 27 had stable sternums, and seven required pectoralis-major muscle flaps. Seventeen patients had unstable sternums; nine required pectoralis flaps, and eight needed either rectus abdominis or omental flap repair of their sternal defects. All patients had spirometry prior to their initial cardiac surgery and could act as their own controls. In both the stable and unstable groups there was no significant difference between preoperative and postoperative respiratory function measured after 6 months. However there was a statistically significant impairment of respiratory function when omental or rectus muscle flap reconstruction was used compared with sternal rewire or pectoralis muscle flap repair. This may have been due to the greater disruption of chest-wall integrity with omental or rectus flap repairs. We conclude that major sternal disruptions can be satisfactorily repaired with flaps of pectoral or rectus muscle or omentum. Repair with omentum or rectus muscle was associated with late impairment of respiratory function.