The aim of this study was to explore whether oropharyngeal dysphagia is a risk factor for community-acquired pneumonia (CAP) in the elderly and to assess the physiology of deglutition of patients with pneumonia. In the case-control study, 36 elderly patients (aged ≥ 70 years) hospitalised with pneumonia were matched by age and sex with two independently living controls. All subjects were given the volume-viscosity swallow test to identify signs of oropharyngeal dysphagia. In the pathophysiological study, all cases and 10 healthy elderly subjects were examined using videofluoroscopy. Prevalence of oropharyngeal dysphagia in the case-control study was 91.7% in cases and 40.3% in controls (p<0.001). Adjusting for functionality and comorbidities, dysphagia showed an independent effect on pneumonia (OR 11.9, 95% CI 3.03-46.9). Among cases in the pathophysiological study, 16.7% showed safe swallow, 30.6% high penetrations, 36.1% severe penetrations and 16.7% silent aspirations during videofluoroscopy, while in the healthy elderly subjects these percentages were 80%, 20%, 0% and 0%, respectively (p<0.001). A delay in closure of the laryngeal vestibule (0.414 ± 0.029 s versus 0.200 ± 0.059 s, p<0.01) was the main mechanism of impaired airway protection. In elderly subjects, oropharyngeal dysphagia is strongly associated with CAP, independently of functionality and comorbidities. Elderly patients with pneumonia presented a severe impairment of swallow and airway protection mechanisms. We recommend universal screening of dysphagia in older persons with pneumonia.