Background CIN leads to increased morbidity, prolonged hospital stay and thereby, more health care costs. The incidence of CIN varies from 2% to 30%. Fortunately, most cases can be completely reversed within two to four weeks. The optimal therapeutics used to prevent and CIN remains unclear. The main objective of the current study is to assess the effect of oral Nicorandil on the occurrence of CIN in patients with renal insufficiency undergoing cardiac catheterization in NSTEACS. Results A prospective study included 100 eligible patients allocated to either the Nicorandil group (n = 50) or the control group (n = 50). Nicorandil group received 20 mg Nicorandil daily (10 mg BID) from 1 day before to 3 days after the procedure with standard intravenous saline hydration for 12 hours before and after the procedure, whereas control group received intravenous hydration only via the same protocol. Serum creatinine and creatinine clearance were measured 24 hours before and (24 hours, 72 hours and 1 week) after the procedure. The eGFR was calculated using the Cockcroft-Gault formula. There was a significant difference as regards CIN occurrence between both groups ,28% in control group and12% in the Nicorandil group. Conclusion The main finding is that in patients with renal impairment, undergoing cardiac catheterization in the setting NSTACS, Nicorandil and adequate hydration is an effective and safe strategy for decreasing the occurrence of CIN in comparison with hydration.