Aim. To investigate the incidence, severity, and prognostic value of acute kidney injury (AKI) in patients with community-acquired pneumonia (CAP). Subjects and methods. A total of 293 CAP patients (185 men and 108 women; mean age 54.3±17.1 years) were examined. AKI was diagnosed and classified in accordance with the 2012 KDIGO guidelines. Results. On admission, the serum concentration of creatinine averaged 104.5±73.3 µmol/l. AKI was diagnosed in 83 (28.3%) patients with CAP. Hospital-acquired AKI was found in 25 (8.5%) patients, which amounted to 30.1% of all the AKI cases. The disease severity according to both the CURB-65 scale and the CRB-65 scale, which neglect blood urea nitrogen concentrations, was higher than that in patients with CAP associated with AKI (1.4±1.0 versus 0.4±0.6 scores; respectively; р