Objective: Previous studies report associations between periodontal infection and cardiorespiratory fitness but no study has examined the association among younger adults. Our objective was to study the association between clinical measures of periodontal infection and cardiorespiratory fitness levels among a population-based sample of younger adults. Methods: The Continuous National Health and Nutrition Examination Survey 1999-2004 enrolled 2,863 participants (46% women) who received a partial-mouth periodontal examination and completed a submaximal treadmill test for the assessment of estimated VO2 max(eVO2 max ). Participants were mean±SD age 33±9 years (range = 20-49 years), 30% Hispanic, 48% White, 19% Black, and 3% other. Mean eVO2 max (mL/kg/minute) as well as eVO2 max≤32 mL/kg/minute (20th percentile) were regressed across quartiles of mean probing depth and mean attachment loss in multivariable linear and logistic regression models. Results: After multivariable adjustment, mean eVO2 max levels±SE across quartiles of attachment loss were 39.72±0.37, 39.64±0.34, 39.59±0.36, and 39.85±0.39 (P = 0.99). Mean eVO2 max±SE across quartiles of probing depth were 39.57±0.32, 39.78±0.38, 39.19±0.25, and 40.37±0.53 (P = 0.28). Similarly, multivariable adjusted mean eVO2 max values were similar between healthy participants vs. those with moderate/severe periodontitis: 39.70±0.21 vs. 39.70±0.90 (P = 1.00). The odds ratio (OR) for low eVO2 max comparing highest vs. lowest quartile of attachment loss = 0.89[95% CI 0.64-1.24]. The OR for comparing highest vs. lowest probing depth quartile = 0.77[95% CI 0.51-1.15]. Conclusion: Clinical measures of periodontal infection were not related to cardiorespiratory fitness in a sample of generally healthy younger adults.