Objective: This study designed to inspect the circulating levels of Cy/C in patients with ACS and to evaluate the association of Cy/C levels with ejection fraction and angiographic number of stenosed coronaries. Methods: 136 participants with ACS were enrolled in this case-control survey and compared with 94 control. Hematological assessments were done for all the participants and included Cy/C, creatinine and uric acid were measured using conventional technique. Creatinine clearance rate was calculated and Estimated glomerular-filtration-rate (eGFR) were measured. Echocardiographic assessment of ejection fraction was done with a cut-off-point <40 LVEF% designated for LV systolic dysfunction. Angiographic evaluation involved in this study depending on the severity of stenosed coronaries by calculating number of arteries display not less than 1 critical stenosis (designed as >70% decrease in caliber). Results: Ejection fraction was significantly lower in in ACS patients than control group (p<0.05). Serum Cy/C was significantly higher in patients' group. The mean plasma uric acids values were significantly higher in patients' group (p-0.001) but with no significant differences in creatinine and creatinine clearance (p>0.05) observed between groups. The eGFR were significantly lower in ACS people compared to healthy persons. Correlation studies of Cy/C showed positive correlation with serum creatinine and serum uric acid; as well as non-significant negative correlation with eGFR (p>0.05). Conclusion: Besides the role of Cy/C in early detection of renal dysfunction, it could have a role in diagnosis of ACS and evaluation of LV systolic dysfunction. Nevertheless, this study showed Cy/C was not related to the number of coronary arteries affected.