This study was conducted in order to determine the outcome of cardiac re-operations in patients over the age of 70. All patients who underwent 're-do' cardiac surgery at our institution, between January 1987 and October 1995 were identified. The case notes of patients over the age of 70 were reviewed retrospectively and follow-up was by telephone. A total of 687 re-do operations were performed during this 8 years and 9 months period. Operations, 110 (16%) were on patients aged 70 years and over (CABG 54, MVR 32, AVR 9, AVR + MVR 5, MVR + CABG 4, AVR + CABG 3, repair of paraprosthetic leak 2 and closure of VSD 1). Operations, 63 (57%) were elective and 42 (38%) were urgent. The median age was 73 years (range 70-82) and 64 patients (58%) were male. Pre-operatively, 78 patients (72%) were NYHA functional class III/IV and 55 (50%) had angiographically impaired left ventricular function (ejection fraction < 50%). The overall operative mortality was 7% (8/110). Median ITU stay was one night (range 1-21) and hospital stay was 7 days (range 5-35). Major in-hospital complications included resternotomy in five patients (5%), permanent stroke in three (3%), renal failure requiring haemodialysis in two (2%) and heart block requiring permanent pacing in two (2%). At a median follow-up of 34 months (range 2-101), 69 of the 77 patients alive at follow-up (90%) were NYHA functional class I/II. 'Re-do' cardiac surgery in patients over the age of 70 carries an acceptable operative morbidity and mortality with a good functional improvement at medium term follow-up.