To explore the role of the IL-23/IL-17 axis in the relationship between periodontitis and coronary heart disease (CHD), 97 subjects were recruited and divided into four groups: (1) CHD + periodontitis, (2) CHD, (3) periodontitus alone, and (4) healthy. The demographic characteristics and periodontal status of all subjects were recorded, and the serum levels of IL-23/IL-17 were detected by enzyme-linked immunoabsorbent assay. Results showed that the serum levels of IL-23/IL-17 in groups 1, 2, and 3 were higher compared with group 4. Group 1 manifested the highest level of serum IL-23/IL-17. A significant positive correlation between IL-23 and IL-17 levels was seen in the three patients groups; groups 1 and 3 also had significant positive correlations with probing depth and attachment loss. The results indicate that there may be an association between periodontitis and CHD, and the IL-23/IL-17 axis may play an important role in the pathologic process of both diseases.