We aimed to investigate whether there were any differences in the percentages of CD14(+) monocytes between subgroups of acute coronary syndromes (ACS). CD14(+) is a monocyte surface receptor that plays a role in the innate immune system. CD14(+) monocytes are associated with complications of atherosclerosis.In total we enrolled 115 patients with ACS: 24 with unstable angina (UA); 29 with non-ST elevation myocardial infarction (NSTEMI); and 62 with ST elevation myocardial infarction (STEMI). The levels of C-reactive protein and percentage of CD14(+) monocyte were measured on admission.CD14(+) monocyte percentages were observed to be different between groups by analysis of variance test. The percentages of CD14(+) monocyte were 81.24+/-10.04% in the UA group; 89.40+/-5.84% in the NSTEMI group; and 87.22+/-11.75% in the STEMI group (P=0.013). The differences between the UA and the NSTEMI and between the UA and the STEMI groups with Bonferroni posthoc testing were significant (P=0.014 and P=0.049 respectively). Moreover, no significant difference was found between the NSTEMI and STEMI groups (P=1.000). The C-reactive protein levels in the UA group were detected to be significantly low with Bonferroni posthoc testing compared with both the NSTEMI and STEMI groups (for both comparisons, P<0.002).A significant difference in CD14(+) monocyte percentages between subgroups of ACS was determined. CD14(+) monocyte percentages can be a useful parameter in differentiating between the subgroups of ACS, especially between UA and myocardial infarction.