Transplant recipients receiving a kidney from an extended-criteria donor (ECD) are exposed to calcineurin inhibitor (CNI) nephrotoxicity, as demonstrated by severe delayed graft function and/or a low GFR. Belatacept is a nonnephrotoxic drug that is indicated as an alternative to CNIs. We reported 25 cases of conversion from a CNI to belatacept due to CNI intolerance within the first 6 mo after transplantation. The mean age of the recipients was 59 years, and 24 of 25 patients received ECD kidneys. At the date of the medication switch, 12 of 25 patients displayed a calculated GFR (cGFR) <15 mL/min, six patients remained on dialysis, and the biopsies showed evidence of acute tubular damage associated with severe vascular or tubulointerstitial chronic lesions. Three patients did not recover renal function, and three patients died during the follow-up period. Among the remaining patients, renal function improved: The cGFR was 18.28 ± 12.3 mL/min before the medication switch compared with 34.9 ± 14.5 mL/min at 1 year after conversion to belatacept (p = 0.002). Tolerance of and compliance with belatacept were good, and only one patient experienced acute rejection. Belatacept is an effective therapy that preserves renal function in kidney transplant patients who are intolerant of CNIs.