Acute decompensated heart failure often coexists with renal failure, and together they increase in-hospital mortality. Sometimes either condition arises because of the decompensation of chronic kidney disease or chronic heart failure. High-dose diuretics along with vasodilators and other medications are the standard first-line therapy but are sometimes ineffective because of the development of diuretic resistance or acute kidney injury. Fluid can be removed with different forms of dialytic techniques, but controversy exists about how and when to perform these procedures. This article explores the risks and benefits of technological approaches and the existing evidence for the best course of action.