The recently concluded Frequent Hemodialysis Network (FHN) trials have demonstrated some striking and unexpected results. Both the daily arm and the nocturnal arm of the trial clearly demonstrated that frequent (daily or nightly) dialysis reduced blood pressure, reduced the number of antihypertensive medications, and reduced serum phosphorous concentration. One of the major questions addressed by these studies was the extent to which left ventricular mass was reduced by frequent dialysis. While the daily FHN trial showed a clear effect of frequent dialysis to reduce left ventricular mass, the nocturnal FHN trial produced inconclusive results. These apparently contradictory results are probably influenced by inadequate power and the somewhat skewed patient selection in the nocturnal arm. Patients in the nocturnal FHN trial had a shorter time on dialysis prior to enrollment, and greater residual renal function than did patients in the daily FHN trial. From a general perspective, it appears that there is minimal difference in the effect on left ventricular mass between frequent daily dialysis and nocturnal dialysis. The FHN trial was not designed to determine the effects of frequent dialysis on mortality. The analyses of this question using retrospective data strongly suggest that frequent dialysis prolongs life. The nephrology community now has the task to develop new ways to deliver improved therapy to patients on dialysis. This task will be challenging as resources for health care are constrained. New approaches to the care of such patients will be needed to realize the important conceptual advances embedded in the results of the FHN trials.