Abstract Background Community-acquired pneumonia (CAP) patients usually present with parapneumonic pleural effusion (PPE), which complicates the treatment of pneumonia. This study aims to investigate the clinical characteristics and risk factors of elderly CAP patients hospitalised with PPE. Methods The clinical data of 132 elderly patients with CAP were retrospectively analysed. A total of 54 patients with PPE (PPE group) and 78 patients without PPE (NPPE group) were included in this study. Clinical data, laboratory examinations, treatments and other relevant indicators were collected. Univariate analysis and multivariate logistic regression analysis will be used to explore the possible risk factors for PPE. Results The proportion of PPE in elderly patients with CAP was 40.9%. PPE patients were significantly more likely to be older, have comorbid neurological diseases, experience chest tightness, and have a lasting fever (P