INTRODUCTION Periodontal disease and elevated C-reactive protein (CRP) tests both are positively correlated with cardiovascular disease (CVD) in many studies. Some health practitioners have concerns that root canal treatment may provide a source for inflammation and hence increase the risk for CVD. AIM To explore the relationship between CRP as a marker of inflammation and presence and number of root canal treatments in primary care patients. METHODS Cross-sectional questionnaire about dental care followed by a blood test for serum CRP in patients from two New Zealand urban family practices. RESULTS One hundred and 34 patients participated. The study showed no significant association between CRP and root canal treatment on multivariate analysis controlling for socioeconomic status, age, gender and smoking. The CRP level for those with > or = 3 root-treated teeth was 1.68 while the level for those with < 3 was 2.36, but the p-value was not statistically significant (p = 0.198). Age, missing teeth and smoking were all significantly related to CRP levels so the sample has biological validity. DISCUSSION Root canal treatment was not associated with higher CRP levels. The CRP levels were non-significantly lower in those with higher numbers of root-treated teeth. While there are a number of potential biases in this paper, the dataset appears to be biologically valid and consistent with known facts. These findings do not support the hypothesis that root canal treatment is associated with higher levels of inflammation. At this point patients should not consider having their root canal teeth removed.