Background: S pneumoniae is the most common cause of community-acquired pneumonia. Aim: To evaluate the clinical characteristics, antibiotic resistance, management and prognostic factors in pneumococcal pneumonia. Methods: Prospective evaluation in 46 adults (age ± sd: 68±17 years) hospitalized with pneumococcal pneumonia confirmed by sputum, blood or pleural fluid cultures. Clinical and radiographic variables, risk factors for antibiotic resistance, and hospital mortality rate were recorded. Results: Heart disease (39%), COPD/asthma (25%), and diabetes mellitus (18%) were the most frequent underlying diseases. None of the patients had previously received pneumococcal vaccine. Only 17% of the patients had the classic triad of chills, fever and productive cough. At admission, interestingly, 17% presented with congestive heart failure. Resistance of pneumococci to penicillin, cefotaxime or erythromycin was 15%, 6% and 11%, respectively. Antibiotic use prior to admission was significantly associated with antibiotic resistance (OR=6; CI 95% = 1.1-32; p <0.05). Fifty per cent of the patients were admitted to intermediate or intensive care units, 15% were mechanically ventilated, 20% developed septic shock, 20% developed acute renal failure and 13% died in the hospital. Clinical factors significantly associated with higher mortality were systolic hypotension (<FONT FACE=Symbol>&pound;</FONT>90 mmHg), ICU admission and BUN >30 mg per dL. Conclusions: Our data suggest that pneumococcal pneumonia is still a severe infection with high mortality; hence, efforts should be made at prevention using pneumococcal immunization (Rev Méd Chile 2003; 131: 505-14).