This study investigates the reasons for hospitalisation in patients with low-risk (CURB-65 score 0-1) community-acquired pneumonia (CAP), with a view to identifying the potential for improving outpatient management. As part of a prospective observational study of CAP, we evaluated reasons for hospitalisation in these low-risk patients. 565 patients had low-risk CAP and 420 of these were admitted (for >12 h). 39.3% had additional markers of severity justifying admission, 29.5% of the admissions were required for further management that could not be provided rapidly in the community, 11.9% had unsafe social circumstances and 19.3% had no clinical reason justifying hospitalisation. 30-day mortality was increased in patients with additional severity markers (6.7%), which was significantly higher compared with 0% for patients awaiting investigations (p=0.009) and 0% without a clear indication for hospitalisation (p=0.04). In a logistic regression analysis, parameters associated with 30-day mortality were chronic cardiac comorbidity (adjusted odds ratio (aOR) 5.73, 95% CI 1.52-21.6; p=0.01), acidosis (aOR 5.14, 95% CI 1.44-18.3; p=0.01), hypoxia (aOR 9.86, 95% CI 2.39-40.7; p=0.002) and multilobar chest radiograph shadowing (aOR 4.54, 95% CI 1.21-17.1; p=0.03). This study supports recommendations from international guidelines that pneumonia severity scores should be used as an adjunct to clinical judgement, when deciding on hospitalisation.