Compliance with validated guidelines is crucial to guide management of patients hospitalized with community-acquired pneumonia (CAP). Data describing real-life management and treatment of CAP are limited. We aimed to evaluate the compliance with guidelines over time, and to assess its impact on all-cause mortality and clinical outcomes. We retrospectively compared two cohorts of patients admitted to the hospital, throughout 2005, just after the implementation of a local clinical pathway based on CAP international guidelines, and 7 years later over 2012. We included all patients with a diagnosis of pneumonia and/or related complications. 564 patients were included. The Pneumonia Severity Index calculation was better documented in 2012 (25.23 %) compared to 2005 (17.70 %; p = 0.032), but compliance with guideline empirical antibiotic therapy was lower in 2012 (56.70 %) than in 2005 (68.75 %; p = 0.004). Performance of guideline recommended urinary antigen tests was higher in 2012, and associated with 57.3 % lower odds of in-hospital mortality (95 % CI 15.0-78.5 %) and with 65.9 % lower odds of 30-day mortality (95 % CI 31.5-83.0 %). Compliance with empirical antibiotic therapy was associated with 2.9 days lower mean length of hospital stay (95 % CI -4.2 to -1.6 days) and with 2.0 days lower mean duration of antibiotic therapy (95 % CI -3.3 to -0.7 days). Compliance with guidelines changed over time, with some effects on mortality and with an apparent reduction in the length of hospital stay and the duration of antibiotic therapy. Specific clinical training and hospital control policies could achieve greater compliance with guidelines, and thus reduce a burden on hospital services.