Heart failure is a major public health problem and is increasing in incidence throughout the industrialized world. Despite recent advances in pharmacotherapy, the overall mortality remains high and largely unchanged. Ultrafiltration has received increased attention in the treatment of acute decompensated congestive heart failure, and recent clinical trials suggest its usefulness in removing volume while preserving renal function. This review will focus on the background of ultrafiltration in the treatment of acute decompensated heart failure as well as the current evidence regarding its efficacy and safety.