C(U)RB-65 (confusion, (urea >7 mol · L(-1),) respiratory frequency ≥ 30 breaths · min(-1), systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg and age ≥ 65 years) is now the generally accepted severity score for patients with community-acquired pneumonia (CAP) in Europe. In an observational study based on the large database from the German nationwide performance measurement programme in healthcare quality, including data from all hospitalised patients with CAP during 2008-2010, different CRB-age groups (≥ 50 and ≥ 60 years) across the total CAP population and three entities of CAP (younger population aged <65 years, patients aged ≥ 65 years not residing in nursing homes and those with nursing home-acquired pneumonia (NHAP)) were validated for their potential to predict in-hospital death. 660 594 patients were investigated. Mortality was n=93 958 (14.0%). In the total population, CRB-80 had the optimal area under the curve (0.690, 95% CI 0.688-0.691). However, in the younger cohort, CRB-50 performed best (0.730, 95% CI 0.724-0.736), with good identification of low-risk patients (CRB-50 risk class 1: 1.28% deaths, negative predictive value 98.7%). In the elderly, CRB-80 as the optimal age group performed worse (0.663, 95% CI 0.660-0.655 in patients not residing in nursing homes; 0.608, 95% CI 0.605-0.611 in those with NHAP). In the latter group, all CRB-age groups failed to identify low-risk patients (CRB-80 risk class 1: 22.75% deaths, negative predictive value 81.8%). Patients with hospitalised CAP aged <65 years may be assessed by the CRB-50 score. In those aged ≥65 years (not NHAP) assessed by the CRB-65 score, low-risk patients are already are at an increased risk of death. In NHAP patients, even the use of CRB-80 does not identify low-risk patients and should be accompanied by the evaluation of functional status and comorbidity.