Background: There is limited information about the effectiveness of the treatment of community-acquired pneumonia (CAP) in Chilean emergency rooms. Aim: To assess the treatment of CAP in emergency rooms at the Vina del Mar Health Service in Chile. Material and methods. Prospective study of immunocompetent adult patients consulting for a CAP in emergency rooms. Those that required hospital admission were considered ineligible. The initial clinical and laboratory assessment, antimicrobial treatment and their condition after 30 days of follow tip, were recorded. Results: Three hundred eleven adult patients aged 57 +/- 22 years (152 males), were evaluated. Patients with class I CAP (40% of cases) were treated with Clarithromycin (71.8%) or Amoxicillin (26.6%) for 10 days. Patients with class II CAP (60%) were treated with Amoxicillin-clavulanate (80.7%) or Levofloxacin (18.2%)for 10 days. Three hundred eight patients (99%) were cured without need of hospital admission; three patients (10%) were subsequently hospitalized because of clinical failure of ambulatory treatment. Overall, three patients (1%) died; all deaths occurred during or immediately after hospitalization and were related to the severity of lung infection but not to the choice of antibiotic treatment. Conclusions. the outpatient management of CAP by general practitioners working at emergency rooms was clinically effective with low rates of hospital admission and mortality.