Alternative hemodialysis (HD) schedules, including short-daily and nocturnal HD, continue to proliferate, with the hope of offering improved patient outcomes. Three nights per week and every other night, nocturnal HD are now being provided to more patients worldwide, both at home and in-center. However, alternative HD schedules are still experimental in most centers, and studies establishing the efficacy of these therapies with respect to major clinical outcomes are needed. Endorsed by the National Institutes of Health, the International Quotidian Dialysis Registry is an international collaboration that was established in 2002 to prospectively study large numbers of patients treated with alternate HD schedules. The Registry will ultimately allow alternate HD modalities to be compared to conventional thrice-weekly HD with respect to clinical endpoints, including mortality, using a prospective cohort study. To date, the Registry has enrolled 182, 1193, and 740 subjects from Canada, the United States, and Australia, respectively. This report is the fourth annual update and describes recruitment progress, baseline characteristics of enrolled patients, and worldwide prescription patterns. ; Gihad E. Nesrallah, Rita S. Suri, Louise M. Moist, Norma J. Ofsthum, Raymond Hakim, Stephen P. McDonald, Mark R. Marshall, Shannon T. Carter and Robert M. Lindsay