Periodontitis is an oral inflammatory disease that may have an association with coronary artery disease (CAD). Oral inflammatory load (OIL) can be quantified by assesment of oral polymorphonucleocytes (oPMN) in an oral rinse assay. The aim of the present study was to prospectively correlate OIL with CAD on angiography assessed in terms of SYNTAX score in patients presenting with stable angina or acute coronary syndrome (ACS). Consecutive eligible patients at a cardiac center were prospectively recruited. Two sets of oral rinse samples were collected before and after angiography, and the relationship between oPMN and SYNTAX score was assessed. Of the 137 patients recruited, 32.8% (n = 45) were female and 34.3% (n = 47) had diabetes mellitus. The overall mean oPMN count was low (mean 1.3 × 10 cells/mL), and the mean SYNTAX score was 7.4 ± 8.5. Most of the patients presented with stable angina (89.8%, n =123). Patients with oPMN ≥1.45 × 10 (periodontitis threshold) were more likely to be elderly males presenting with stable angina. No significant correlation was established between oPMN and SYNTAX score. Although this prospective study did not demonstrate a correlation between OIL and the severity of CAD, most patients had low mean oPMN values. Larger studies are required before definite conclusions can be drawn.