Renal replacement therapies (RRT) are a key component of the therapeutic approach to acute renal failure (ARF) in the intensive care unit (ICU), and they are usually performed as classic Intermittent (intermittent hemodialysis) or continuous RRT (such as for example continuous venovenous hemofiltration, CVVH). No clear evidence exists on what the first-choice RRT option should be for ICU patients with ARF. Alternative strategies have been developed, under the form of intermittent prolonged RRT, with the aim of providing easy to perform, highly efficient, and less expensive RRT in the ICU. In this review we put forward the hypothesis that hybrid RRT, such as sustained low-efficiency dialysis ( sLED), could offer a valuable alternative to the currently available strategies in the critically ill with ARF.