Introduction. Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality after percutaneous coronary intervention (PCI). On the other hand, CIN is a serious complication in patients with diabetes or renal impairment undergoing percutaneous coronary intervention (PCI). CIN after PCI may be associated with prolonged hospitalization, increased rates of kidney injury, and short- and long-term mortality. Factors that have been associated with CIN include: diabetes mellitus, congestive heart failure, recent acute myfocardial infarction, cardiogenic shock, and pre-existing renal impairment. In this study, we investigated contrast nephropathy development after coronary angiography (CAG) in patients presenting with acute coronary syndrome, who were hospitalized initially in the Coronary Care Unit and subsequenttly referred to the Internal Medicine Clinic in a tertiary care hospital.;Methods. We’ve analyzed 335 patients’ records retrospectively in 1 year that were followed-up with acute coronary syndrome (ACS) in the Coronary Care Unit (CCU) and transferred to the Internal Medicine Clinic (IMC). The following parameters were evaluated: age, gender, chronic disease and drug history, biochemical values evaluated before hospitalization to CCU, ejection fraction (EF) and left atrium diameter (LA), with or without previous CAG; values of serum creatinine (sCr) levels before CAG and after 48 hours. Values of p <0.05 were considered to be significant.;Results. 126 of 335 patients were female and 209 were male. The average age of patients was 64.2 years. 122 patients used angiotensin converting enzyme inhibitor (ACEI), 54 patients used furosemide. CIN development rate of CAG patients was 22.8; (n=54). There was no significant relationship with age, gender and chronic disease history in CIN patients. When laboratory findings were compared, there was no significant relationship except for potassium value before CAG. However, potassium values were significantly higher in CIN patients (p=0.001). When drug usage of patients was compared, 48.1; (n=26) of CIN patients used ACEI and there was a significant relationship between ACEI use and CIN development (p=0.026).;Conclusions. CIN development rate was 22.8; and it was relatively high when compared with literature data. Awareness about contrast nephropathy develepment risk and assessment of risk factors before the procedure should be increased in our Center.“,”