Objective To evaluate the effect of contrast medium on the renal function in patients with cerebrovascular disease accompanied by diabetes mellitus after receiving neuro - interventional therapy. Methods The clinical data of a total of 108 patients with cerebrovascular disease complicated by diabetes mellitus type 2, who were treated with neuro - interventional therapy during the period from March 2013 to March 2016, were retrospectively analyzed. The contrast dose used in interventional procedures was less than 250ml in each patient. The preoperative and 24 h -postoperative serum creatinine (sCr), serum cystatin C (Cys C) levels were determined, and based on the modification of dietary renal disease (MDRD) equation and Larsson equation the estimated glomerular filtration rates (eGFR) were separately calculated. Results Compared with preoperative values, the 24 h - postoperative mean sCr and Cys C levels were increased significantly (P=0. 001, P=0. 015 respectively), while the average eGFR rates were remarkably decreased (P＜ 0. 000 1 by using MDRD equation, and P=0. 021 by using Larsson equation). No kidney damage that needed to be treated occurred in all patients. Conclusion The contrast dose used in neuro - interventional procedures can cause decline of renal function in patients with type 2 diabetes mellitus. The combined determination of sCr and Cys C levels is helpful for the detection of contrast - induced changes in renal function as early as possible. The use of conventional dose of contrast agent in neuro - interventional procedures is safe for patients with type 2 diabetes mellitus. (J Intervent Radiol, 2018, 27:277-280)