Despite advances in the management of cardiovascular diseases, acute coronary syndrome (ACS) remains the leading cause of death worldwide. ACS is associated with an imbalance between coronary blood supply and metabolic requirements. Lipid peroxidation and production of reactive oxygen species (ROS) damage the cardiac cell membrane. A total of 130 subjects, 65 ACS patients (45 with ST segment elevation (STE-ACS), 20 non-STE-ACS), and 65 healthy controls were recruited. Measurement of serum zinc, total antioxidant capacity (TAC) and malondialdehyde (MDA) by spectrophotometric methods 24 h after onset of ACS, and relations between the studied biochemical parameters and risk factors were performed. MDA levels were significantly increased; TAC and zinc levels were significantly decreased in ACS patients compared to the controls (P < 0.001 for each). No significant difference was detected between the different types of ACS and each of the oxidative stress parameters, cardiac biomarkers, lipogram, and risk factors. Only serum zinc in STE-ACS patients was significantly lower compared with NSTE-ACS patients (P < 0.001). Serum zinc showed the greatest AUC (area under the ROC curve) of 0.926 with 76.92% sensitivity and 95.38% specificity. Negative and positive correlations between MDA and zinc and between TAC and zinc levels respectively (P < 0.01) were found in ACS. Week negative correlation was observed between serum zinc and SYNTAX score (r = − 0.434, P = 0.049). Our results indicate that deficient serum zinc concentration strongly associated with the etiopathogenesis of ACS.