Glioblastoma multiforme is an aggressive malignant brain tumor. The monoclonal antibody, bevacizumab, is active in recurrent disease via inhibition of angiogenesis. Proteinuria and renal thrombotic microangiopathy are known complications. We report a case of a patient developing acute renal failure with biopsy-proven interstitial nephritis while receiving bevacizumab for recurrent disease. The patient was otherwise well with a history of controlled hypertension. Renal function improved with discontinuation of bevacizumab and the administration of corticosteroid therapy.