The aims of this work are to describe the clinical, biological and radiological features of community-acquired (CA) Legionnaires" disease (LD) and identify the predictors of mortality in hospitalised patients.Demographic data, risk factors, clinical, and biological features, medical management, complications and outcome from 540 hospitalised patients with confirmed CA LD were prospectively recorded.8.1% of patients (44/540) died. The predictors of survival after Kaplan-Meier analysis were male gender (P=.01), age <60 years (P=.02), general symptoms (P=.006), intensive care unit (ICU) stay (P<.001), and class II-III pneumonia severity index score (P=.004). Six predictors of death were identified by multivariate analysis: age (per 10-year increments) (relative hazard (RH), 1.50; 95% confidence interval [95% CI], 1.21-1.87), female gender (RH, 2.00; 95% CI, 1.08-3.69), ICU admission (RH, 3.31; 95% CI, 1.67-6.56), renal failure (RH, 2.73; 95% CI, 1.42-5.27), corticosteroid therapy (RH, 2.54; 95% CI, 1.04-6.20) and C-reactive protein (CRP) >500 mg·L(-1) (RH, 2.14; 95% CI, 1.02-4.48). Appropriate antibiotic therapy was prescribed for 76.3% (292/412) of patients after admission and for 99.6% (537/538) of patients after diagnosis confirmation.In conclusion, female gender, age, ICU stay, renal failure, corticosteroid treatment, and increased level of CRP are significant risk factors for mortality in CA LD. (R.A.)