Severe hypertension prior to renal transplantation has traditionally been an indication for bilateral nephrectomy. The reasons for hypertension after successful renal transplantation are however many, and the impact of simultaneous bilateral nephrectomy (BN) in this setting has not been well documented. We retrospectively evaluated 158 living-donor renal graft recipients. BN had been performed in 76 patients at the time of the transplantation and 82 were not nephrectomized (controls). All received a triple immunosuppressive drug regimen. Before transplantation, patients in the BN group used 1.8 +/- 0.9 (mean +/- SD) antihypertensive drugs/day, significantly more than in the control group (1.3 +/- 0.8; P < 0.05). Three months after renal transplantation no difference was found (0.9 +/- 1.0 drugs/day in the BN group vs 1.0 +/- 0.8 drugs/day in the control group). No difference was found with respect to serum creatinine, whole blood cyclosporin A (CsA) concentration or blood pressure between the groups. The number of blood transfusions during the first week after transplantation was significantly increased in the BN group (66 SAG units vs 4 SAG units). The median hospitalization length was also longer in the BN group (21 days vs 16 days). In order to circumscribe the pre-transplant difference in use of antihypertensive medication we studied a subgroup of 62 hypertensive recipients (BN/control = 31/31) matched for number of antihypertensive drugs at the time of transplantation (2.3 +/- 0.5 drugs/day in the BN group, 2.1 +/- 0.3 drugs/day in the control group). Three months after transplantation the use of antihypertensive drugs remained the same in the two groups (1.3 +/- 1.0 drugs/day in the BN group vs 1.3 +/- 0.9 drugs/day in the control group). At 3 months no difference was found between the two hypertensive subgroups regarding serum creatinine, whole blood CsA and haemoglobin concentration or systolic blood pressure. However, the BN patients were younger than the control group (38 +/- 10 years vs 49 +/- 11 years, P < 0.05) and this may explain the marginally lower diastolic blood pressure observed in the BN group (82 +/- 10 mmHg vs 87 +/- 7 mmHg, P < 0.05). It is concluded that, in recipients of living-donor grafts, bilateral nephrectomy performed at the time of transplantation did not influence the number of antihypertensive drugs used 3 months after a successful transplantation. Bilateral nephrectomy did however increase the need of blood transfusions during the first week after transplantation and also the hospitalization length.