BACKGROUND In a prospective randomised clinical study we assessed and compared antegrade vs. combined antegrade-retrograde cardioplegia in patients who underwent elective coronary artery by pass grafting. METHODS Between March 2006 and January 2007, 87 consecutive patients were randomly divided into two groups. Group A (n=45) received antegrade cold (4 degrees C) blood cardioplegia. Besides antegrade cardioplegia, Group B (n=42) received continuous retrograde cardioplegia passively by gravitational force. The need for cardiac support during and after cardiopulmonary bypass, post-operative morbidity, ICU stay, hospital stay and mortality were compared in two groups. RESULTS There was no significant difference between the two groups in gender, age and pre-operative ejection fraction. Sixteen patients in Group A (35.5%) and eight patients in Group B (19%) needed inotropic support while weaning off cardiopulmonary bypass (p=0.04). Four patients in Group A (8.9%) and two patients in Group B (4.8%) needed intra-aortic balloon pump (p=0.44) in the ICU. We found no statistically important difference between the two groups in post-operative morbidity and mortality. CONCLUSIONS Retrograde continuous infusion of cardioplegia by gravitational force combined with antegrade cardioplegia, provides satisfactory myocardial protection and eliminates the need for inotropic support compared with antegrade technique alone.