Whilst the potential risk to underlying vital structures from redo-sternotomy is well recognized, the actual risk is poorly quantified. Our aim was to determine the incidence of complications directly attributable to redo-sternotomy and to ascertain whether the use of femoro-femoral CPB (FF) prior to redo-sternotomy alters operative morbidity and mortality. Case notes of 185 patients undergoing cardiac surgery necessitating redo-sternotomy between May 1998 and November 2002 were reviewed. Of 121 males and 64 females, the median age was 65.5 years (range 60.1-75 years). Elective FF was performed in 71 (38.3%) of cases and 114 (60%) were performed without the aid of prior femoro-femoral CPB (WFF). Three (1.6%) patients initially planned for WFF were converted to emergency FF due to serious complications. Complications directly attributable to redo-sternotomy occurred in 21 (11.3%) cases; 12 (16.9%) in the FF group and 9 (5.3%) in the WFF group. Overall mortality was 1.6%. In summary, our results suggest that morbidity risk for the operation increases significantly with redo-sternotomy alone. Three deaths in our series from direct complications attributable to redo-sternotomy signify an added risk. Hence the necessity for careful surgical technique and judicious use of elective FF-CPB is emphasized.