Rejection reaction is an important complication in heart transplantation. Recent physiopathological findings suggest new immunosuppressive alternatives such as the use of substances that block interaction between leukocytes and endothelium or subsequent events. The objective of this work was to evaluate the effect of the combination of dextran 60 and conventional immunosuppressive therapy.We used Sprague-Dawley rats, both sexes, with mean weight of 317.3 +/- 31.3 g on which we carried out heterotopic heart transplantation and then randomized into four groups. All groups received cyclosporine (2 mg/kg/day) and prednisone (0.5 mg/day). Group I (n = 5) also received 0.5 cc/kg/day of dextran 60, group II (n = 5) 1.0 cc/kg/day of dextran 60, group III (n = 5) 2 cc/kg/day, and group IV (n = 4) 0.9% saline solution 0.5 cc/kg/day. The incidence and severity of rejection reaction was evaluated as survival of transplanted hearts.Significant differences were found between groups III and IV for incidence of rejection reaction (p = 0.039). However, there were no differences among groups (grade 3A or 3B) in the magnitude of the rejection reaction. Survival of hearts was better in all groups receiving dextran 60 (p = 0.031).It was concluded that dextran 60 improves survival of transplanted hearts and decreases incidence of rejection reaction.