Résumé : Background There are no studies that describe the impact of the cumulative fluid balance on the outcomes of cancer patients admitted to intensive care units ICUs. The aim of our study was to evaluate the relationship between fluid balance and clinical outcomes in these patients. Method One hundred twenty-two cancer patients were prospectively evaluated for survival during a 30-day period. Univariate (Chi-square, t-test, Mann-Whitney) and multiple logistic regression analyses were used to identify the admission parameters associated with mortality. Results The mean cumulative fluid balance was significantly higher in non-survivors than in survivors [1675 ml/24 h (471-2921) vs. 887 ml/24 h (104-557), P = 0.017]. We used the area under the curve and the intersection of the sensibility and specificity curves to define a cumulative fluid balance value of 1100 ml/24 h. This value was used in the univariate model. In the multivariate model, the following variables were significantly associated with mortality in cancer patients: the Acute Physiology and Chronic Health Evaluation II score at admission [Odds ratio (OR) 1.15; 95% confidence interval (CI) (1.05-1.26), P = 0.003], the Lung Injury Score at admission [OR 2.23; 95% CI (1.29-3.87), P = 0.004] and a positive fluid balance higher than 1100 ml/24 h at ICU [OR 5.14; 95% CI (1.45-18.24), P = 0.011]. Conclusion A cumulative positive fluid balance higher than 1100 ml/24 h was independently associated with mortality in patients with cancer. These findings highlight the importance of improving the evaluation of these patients' volemic state and indicate that defined goals should be used to guide fluid therapy. © 2012 The Acta Anaesthesiologica Scandinavica Foundation.