Background. Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II type 1 receptor blockers (ARB) decrease cardiovascular mortality and slow the progression of renal disease in non-transplant patients, but their impact on kidney transplant outcome has not been well established.Methods. Patients receiving a renal allograft in Spain in 1990, 1994, 1998 and 2002 were considered for the present study. Only adult (>/=18 years) recipients of a single kidney transplant functioning at the end of the first year were considered. A total of 4842 patients with clinical data about ACEI/ARB therapy were included.Results. During the initial 2 years after transplant, ACEI/ARB were less frequently used in the 1990 and 1994 cohorts than in 1998 and 2002 (15.1%, 24.6%, 33.5% and 45.1%, respectively; P < 0.001). During the first year, a total of 1063 patients (22.8%) received ACEI/ARB treatment, and graft survival (50.0% for treated patients and 51.4% for untreated, P = ns), death-censored graft survival (60.6% versus 63.5%, P = ns) and patient survival (68.8% versus 66.6%, P = ns) were not different. During the initial 2 years, 1472 patients (31.4%) received treatment with ACEI/ARB, and graft survival tended to be higher in treated patients (54.4% and 50.9%, P = 0.063). Since there was an interaction between ACEI/ARB treatment and year of transplant, graft survival was analysed in each cohort. Cox regression analysis including the propensity score for ACEI/ARB treatment showed an association between ACEI/ARB treatment and graft survival in the 2002 cohort (relative risk 0.36 and 95% confidence interval 0.17-0.75, P = 0.007). Death-censored graft survival (63.8% versus 63.1%, P = ns) and patient survival (68.1% and 66.5%, P = ns) were not significantly different.Conclusions. The use of ACEI/ARB during the initial 2 years after transplantation was associated with a better graft survival, but this effect was only observed in the 2002 cohort.