Patients with established diabetic nephropathy could have other glomerular diseases superimposed on diabetic glomerulosclerosis. Cholesterol embolization syndrome (CES) is a systemic disorder caused by cholesterol crystal embolization from ulcerated atherosclerosis plaques in the aorta and its major branches. Curiously, there are few papers describing the association between diabetic nephropathy and CES. On the other hand, the clinical picture of CES resembles systemic vasculitis, and there is a controversy regarding the association between CES and glomerular or vascular inflammation. We report a case of atypical CES that developed after cardiac catheterization in a diabetic man; it presented as subacute renal failure with proliferative and exudative endocapillary glomerulonephritis.