OBJECTIVES: Cancer patients are at high risk for acute kidney injury (AKI), which is associated with high mortality when renal replacement therapy is required. Because physicians might be reluctant to offer dialysis to patients with malignancies, we sought to appraise outcomes in critically ill cancer patients (mainly with hematological malignancies) who received renal replacement therapy for AKI complicating cancer management. DESIGN: Cohort study including consecutive patients who received renal replacement therapy for AKI complicating cancer management, over a 42-month period. Their mortality was compared with that of non-cancer patients who received renal replacement therapy in the same center over the same study period (control group). SETTING: A 12-bed medical intensive care unit in a university hospital. RESULTS: 94 critically-ill cancer patients met the inclusion criteria. Median SAPS II was 53 (IQR 40-75) and median Logistic Organ Dysfunction score was 7 (IQR 5-10). The etiology of AKI was multiple in most patients (248 identified factors in 93 patients). Hospital mortality was 51.1%. Two variables were independently associated with hospital mortality: the severity of associated organ failures at ICU admission (OR, 1.33; 95% CI, 1.11-1.59; per point) and renal function deterioration after ICU admission (OR, 5.42; 95% CI, 1.62-18.11). Characteristics of the malignancy were not associated with hospital mortality. The presence of cancer had no detectable influence on hospital mortality after adjustment for gender, age, acute severity as assessed by the SAPS II score, and chronic health status [OR 1.2, 95% CI 0.63-2.27; p=0.57]. CONCLUSION: ICU admission should be considered in selected critically ill cancer patients with AKI requiring renal replacement therapy.