Oral health can affect or be a manifestation of general health. Although oral health assessment has been used as a proxy for general health, few studies have reported an association between oral health status and allergic diseases. This cross-sectional study aimed to investigate the relationship between subjective oral health status and asthma/allergic rhinitis in a nationwide representative sample of Korean adults.A total of 227,977 participants from the Korean Community Health Survey 2015 were enrolled. Participants were asked about their subjective oral health status (very good, good, normal, poor, very poor), periodontal status (mobility, swelling, calculus, bleeding), teeth brushing frequency, and scaling history within the past 12 months. Histories of physician-diagnosed asthma and allergic rhinitis throughout life were surveyed. The associations between subjective oral health status and allergic diseases were analyzed using multiple logistic regression analysis. Age, sex, economic level, educational level, region of residence, smoking, alcohol, obesity, subjective general health status, stress level, physical activity, periodontal status, teeth brushing frequency, and scaling history within the past 12 months were adjusted as covariates.A higher prevalence of asthma (3.6%) was reported in the poor oral health group than in the good (1.8%) and normal (2.1%) groups (P < .001). Poor oral health status was significantly related to asthma, with an adjusted odds ratio (aOR) of 1.19 (95% CI = 1.07-1.33, P = .002). Although the prevalence of allergic rhinitis was not higher in the poor oral health group (13.4%) than in the good (15.4%) and normal oral health groups (15.9%), the aOR for allergic rhinitis was 1.05 (95% CI = 1.00-1.11, P = .045) in the poor oral health group after adjusting for covariates.Subjective poor oral health status was significantly associated with asthma and allergic rhinitis in Korean adults.