Objectives The oral cavity is a potential reservoir for respiratory pathogens which can predispose patients to bacterial super-infection. Several trials have correlated poor oral hygiene with hyper-inflammation. Similarly, COVID-19 severity has been linked to hyper-inflammatory responses. Hence, in this study, we assumed that increased COVID-19 severity may be linked to poor oral health status. This was achieved through assessing oral health status, severity of COVID-19 symptoms, C-reactive protein (CRP) levels and duration of recovery.Methods Cross-sectional study based on a questionnaire; 308 Egyptian patients with confirmed positive polymerase chain reaction (PCR) tests were included in the study after exclusion criteria. The questionnaire was designed with two sections: the first section for oral health evaluation and the second section for COVID-19 severity evaluation. Assessment of the effect of oral health on COVID-19 severity was performed using an oral health score. The effect of oral health on CRP and recovery period were evaluated as secondary endpoints. Data of CRP levels and COVID-19 PCR tests were collected via the questionnaire and confirmed by reviewing medical records.Results The correlation between oral health and COVID-19 severity showed a significant inverse correlation (p <0.001, r = -0.512). Moreover, the correlation between oral health with recovery period and CRP values also revealed a significant inverse correlation (p <0.001, -0.449 and p <0.001, -0.190, respectively), showing that poor oral health was correlated to increased values of CRP and delayed recovery period.Conclusions Our study provided some evidence that oral health could have a potential impact on the severity of COVID-19. However, the correlation is limited by the study design. A more substantial research project is required to address this relation.