Background: Serum creatinine elevated by more than 25% or ≥0.5 mg/dl absolute from baseline within 48 hours of contrast administration is known as contrast-induced nephropathy (CIN). It is the third most common cause of iatrogenic acute kidney insult in hospitals and raises the risk of subsequent renal injury, length of hospitalization, and mortality rate, particularly in cardiac patients with multiple comorbidities (1). Many factors related to both the patient and the contrast affect the incidence of CIN; one of the independent risk factors is diabetes mellitus DM)(2). Aim: to evaluate the impact of diabetes mellitus on the incidence of CIN in cardiac patients to improve the patients' outcomes. Subjects and Methods: pre-post study that included 62 patients recruited from the cardiac catheterization unit of Suez Canal University Hospital, Ismailia City, to assess the risk of CIN among diabetic and non-diabetic patients following coronary interventions. Results: The incidence of CIN in the study was 9.7%. There was no statistically significant difference in DM or its duration between the CIN and non-CIN groups. Glycemic control is crucial, as found by the statistically significant differences in HbA1C levels between CIN and non-CIN groups. The study found that the most significant risk factors for CIN were low EF%, anemia, high serum cholesterol, advanced age, and chronic kidney disease. Conclusions: Glycemic control is one of the most important risk factors for the development of CIN as opposed to DM and its duration; strict glycemic control may improve patient outcomes.