The incidence and prevalence of heart failure are continuously on the increase. Pharmacological therapy is not sufficient in the advanced stages of the illness to control the signs and symptoms, especially when stressing factors intervene and complicate the illness course. Dialytic treatments are always indicated more than necessary in the severe forms of heart failure, but the optimal treatment has not yet been established. In our division, 24 patients with heart failure (III-IV NYHA) and renal failure (III-IV NKF-DOQI) were treated with low flux bicarbonate dialysis, variable dialysate and limited ultra-filtration. Arrhythmia, pericarditis, ischemic cardiopathy and hyponatremia were the stressing factors that determined acute heart failure. Fifteen patients presented with diastolic failure, whereas nine patients had systolic heart failure. The first group of patients had higher arterial pressure, better ejection fraction and better prognosis regarding renal function and survival rate. The results obtained with this treatment in prevalently diastolic heart failure are satisfactory in terms of survival, as well as in renal function recovery, whereas they are not adequate in systolic failure where other approaches are being studied. Therefore, we believe that the therapeutic choice must always be determined in relation to the type of heart failure.