In previous studies, we showed that in African-American patients arterial hypertension during the first 6 months after transplantation is associated with a high risk of renal allograft loss. In this study, we sought to examine the relationships between pretransplant blood pressure (preBP), blood pressure early after transplantation (postBP), and allograft function and survival. The study included 116 African-American recipients of first cadaveric renal allografts followed for 64 +/- 40 months. Prior to transplantation, 78% of the patients required antihypertensive medications and 59% had poorly controlled BP (average mean arterial pressure, > or =107 mm Hg). Blood pressure levels increased significantly during the first month posttransplant, particularly in patients with poorly controlled preBP. During the first 6 months posttransplant, 95% of patients required antihypertensive drugs; after the transplant, patients required significantly more and higher doses of antihypertensives compared with pretransplant. In 38% of the patients, postBP remained high despite therapy. The level of postBP correlated with the patient's weight pretransplant and with the level of preBP. Pretransplant BP correlated with postBP 1 month after transplantation (r = 0.4, P < 0.0001), and 70% of the patients with poorly controlled postBP had uncontrolled preBP. Patients with poorly controlled preBP had worse graft survival than patients with well-controlled preBP (P = 0.03 by Cox regression). Furthermore, compared with patients with well-controlled postBP, patients with high postBP had higher serum creatinine at 10 days (P = 0.04) and at 6 months (P = 0.0004) posttransplant; these patients had reduced graft survival (P = 0.0006 by Cox). We found no objective evidence of differences in patient compliance between individuals with high postBP and those with well-controlled postBP. This study confirms the association between high postBP and reduced renal allograft survival in African-American patients. In addition, these results show that the level of preBP can be used to identify patients at high risk of developing severe hypertension immediately after transplantation and those at risk for renal allograft failure.