BACKGROUND The incidence of delayed graft function in cadaveric grafts has increased over the last few years due in part to the large demand for cadaveric kidneys necessitating the use of kidneys from marginal donors. Calcium channel blockers have the potential to reduce the incidence of post-transplant acute tubular necrosis (ATN) if given in the peri-operative period. However, there is controversy surrounding their use in this situation with no consensus as to their efficacy. OBJECTIVE To evaluate the benefits and harms of using calcium channel blockers in the peri-transplant period in patients at risk of ATN following cadaveric kidney transplantation. METHODS We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library issue 2, 2003) MEDLINE (1966 to January 2003) and EMBASE (1980 - January 2003). The Trials Search Coordinator was contacted to develop the search strategy. METHODS Randomised controlled trials comparing calcium channel blockers given in the peri-transplant period with controls were included. Quasi-randomised trials were excluded. METHODS Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as weighted mean differences (WMD) with 95% confidence intervals (CI). RESULTS Nine trials were suitable for inclusion. Treatment with calcium channel blockers in the peri-transplant period was associated with a significant decrease in the incidence of post transplant ATN (RR 0.57, 95%CI 0.40 to 0.82) and delayed graft function (RR 0.44, 95% CI 0.28 to 0.69). There was no difference between control and treatment groups in graft loss, mortality, requirement for haemodialysis. There was insufficient information to comment on adverse events. CONCLUSIONS These results suggest that calcium channel blockers given in the peri-operative period may reduce the incidence of ATN post-transplantation. The result should be treated with caution due to the heterogeneity of the trials which made comparison of studies and pooling of data difficult.