Objective To explore the association of depression and anxiety with two oral health outcomes, dental caries and periodontal disease and assess possible mediators for any of the associations. Methods Secondary analysis of the Finnish Health 2000 Survey. Depression was assessed with Beck's Depression Inventory and anxiety with Composite International Diagnostic Interview. Number of decayed teeth included carious lesions reaching dentine; periodontal disease was number of teeth with periodontal pockets of 4 mm or deeper. Third molars were excluded. The association of mental disorders and oral health was tested in regression models adjusted for confounders and potential mediators. Results Depression was associated with number of decayed teeth only among 35- to 54-year-olds. The association between anxiety and the number of decayed teeth was not statistically significant. Depression and periodontal pocketing were not significantly associated. Conclusion Depression was significantly associated with number of decayed teeth only among participants aged 35-54 old and not with other age groups. Neither depression nor anxiety was significantly related to periodontal disease.