Sternal dehiscence is a recognized complication of median sternotomy in 2.5-4.8% of patients. The authors describe the prognostic significance of a lucent midsternal stripe which was seen in 12 patients over a two-year period. Sternal dehiscence requiring surgical revision developed in 4, and radiological suspicion preceded clinical evidence of dehiscence in 3 of them. A review of 100 consecutive median sternotomies revealed that sternal dehiscence did not develop in any patient who did not have a midsternal stripe. It is suggested that this may be a useful tool in identifying those patients who are at high risk of the development of sternal dehiscence.