Acute oxalate nephropathy is a severe cause of acute kidney injury characterized by tubule-interstitial oxalate deposits with an inflammatory infiltrate. Three cases of AKI occuring in diabetic patients, and whose renal biopsy gave a diagnosis of acute oxalate nephropathy are reported. This cristal deposit AKI is due to either primary hyperoxaluria or secondary to enteric hyperabsorption. Its prognosis is dismal and rapid recognition by renal biopsy and determination of the cause of hyperoxaluria is mandatory in order to avoid end-stage kidney disease. This diagnosis should be suspected in cases of non resolving AKI, especially in diabetic patients who may have undetected pancreatic exocrine insufficiency.