OBJECTIVE: To establish a prognostic scoring system for septic shock patients. DESIGN: The clinical, biological, and hemodynamic data of these patients were retrospectively explored to select variables independently associated with outcome. According to the risk of death, ratings from 0 to 2 points were attributed to each value. SETTING: Medical intensive care service of a 1,000-bed tertiary care university medical center. PATIENTS: Eighty-eight patients in septic shock in whom hemodynamic measurements were performed using pulmonary artery flotation catheters. RESULTS: Fourteen clinical, biological, and hemodynamic variables were selected and rated for each patient. A Simplified Septic Shock Score, available immediately after admission and catheterization, was established by adding the rates of these variables. The mean Simplified Septic Shock Score was 2.5 +/- 1.7 (SD) in 43 survivors and 6.5 +/- 2.3 in 45 nonsurvivors (p less than .0001). Some underlying diseases and characteristics of infections also correlated with the outcome. Further ratings from 0 to 2 points were attributed to these conditions. A Complete Septic Shock Score was calculated by adding these rates to the Simplified Septic Shock Score. The Complete Septic Shock Score had a slightly better prognostic value than the Simplified Septic Shock Score, but it could be determined only after the availability of the microbiological data. The mean Complete Septic Shock Score was 3.1 +/- 1.9 in survivors and 8.4 +/- 2.6 in nonsurvivors (p less than .0001). Both Simplified and Complete Septic Shock Scores showed better association with patient outcome than the Simplified Acute Physiology Score or the Acute Physiology and Chronic Health Evaluation (APACHE II) score. CONCLUSIONS: The Simplified and the Complete Septic Shock Scores are simple scoring systems that appear to predict the outcome of septic shock patients more accurately than general scoring systems, such as the Simplified Acute Physiology Score and APACHE II score. These septic shock scores might be useful in assessing the severity of septic shock patients.