OBJECTIVE To analyse the characteristics and mortality-related factors in a series of patients hospitalized for pyogenic liver abscess (PLA). BACKGROUND Pyogenic liver abscesses are infrequent but potentially life threatening. Factors related to mortality have been less studied. METHODS The medical records of 84 patients, 56 men and 28 women, mean age of 64.4 years (SD: 14) who were hospitalized between 1992 and 2005 owing to a PLA were reviewed. The past medical history, clinical signs and symptoms, laboratory values, imaging studies, microbiological features, treatment, complications and mortality were recorded. Factors related to complications and mortality were analysed. RESULTS One or more bacteria were isolated in 65 patients (77.4%), being Streptococcus spp. (40.5%), Escherichia coli (27.4%), Klebsiella spp. (14.3%) and anaerobics (17.9%) the most frequent isolates. Complications developed in 60.7% of the cases, the most common one being a right pleural effusion (34.5%). Mortality rate was 19% (95% confidence interval: 10-28%). Mortality was associated with age (P=0.005), a previous history of coronary heart disease (P=0.016), absence of fever (P=0.001), development of sepsis and/or septic shock (P<0.001), raise of bilirubin levels (P=0.004), a biliary (P=0.035), or cryptogenetic origin (P=0.039), infection owing to E. coli (P=0.01) or to Candida (P=0.009) and development of pneumonia (P<0.001). Logistic regression revealed sepsis and/or septic shock as an independent risk factor for mortality. CONCLUSIONS Mortality associated with PLA is high. The main risk factor for mortality is the development of sepsis and/or septic shock.