A total of 200 patients (131 males and 69 females), scheduled for cardiovascular surgery were randomly assigned to receive either sulbactam/ampicillin 1 g IV of cefuroxime 2 g IV before the surgical incision and then, postoperatively, 8-hourly x 3 days. There were five failure of prophylaxis (all in the cefuroxime group): 3 sternal incision abscesses (1 Pseudomonas aeruginosa and 2 Staphylococcus epidermidis), one urinary tract infection (Staphylococcus aureus) and one Micrococcus pneumoniae. Tolerance to both antibiotics was excellent. In our sample of patients, the efficacy and safety of sulbactam/ampicillin were not different from those of cefuroxime in prophylaxis in cardiovascular surgery.