Although there is a perception that the use of peritoneal dialysis is declining worldwide, compilations of global data are unavailable to test this hypothesis. We assessed longitudinal trends in the use of peritoneal dialysis from 1997 to 2008 in 130 countries. The preferred data sources were renal registries, followed by nephrology societies, health ministries, academic centers, national experts, and industry affiliates. In 2008, there were approximately 196,000 peritoneal dialysis patients worldwide, representing 11% of the dialysis population. In total, 59% were treated in developing countries and 41% in developed countries. Over 12 years, the number of peritoneal dialysis patients increased in developing countries by 24.9 patients per million population and in developed countries by 21.8 per million population. The proportion of all dialysis patients treated with peritoneal dialysis did not change in developing countries but significantly declined in developed countries by 5.3%. The use of automated peritoneal dialysis increased by 14.5% in developing countries and by 30.3% in developed countries. In summary, the number of patients treated with peritoneal dialysis rose worldwide from 1997 to 2008, with a 2.5-fold increase in the prevalence of peritoneal dialysis patients in developing countries. The proportion of all dialysis patients treated with this modality continues to decline in developed countries. Chronic dialysis is a life-sustaining treatment for patients with ESRD. Access to dialysis remains limited in several regions of the world due to a lack of financial and clinical resources. [1][2][3][4][5][6][7][8][9] As countries look to develop dialysis programs to manage the growing burden of ESRD, it is important to place patterns of peritoneal dialysis (PD) use in the global context. This information is particularly helpful to individuals in member nations responsible for health care delivery to evaluate their PD programs through comparisons with countries of similar socioeconomic structure.A comprehensive global assessment of PD use to date has been lacking. One study suggested that 11% of chronic dialysis patients around the world are treated with PD. 10 Several renal registries report PD use at a national and regional level, 11-14 but not on a global scale. There is a perception that PD use is declining worldwide. However, studies that showed declining PD use in the developed world are limited by the number of countries considered and the length of time examined. 3,[15][16][17] No study has examined the global use of different PD modalities over a significant period of time, including continuous ambulatory PD (CAPD) and automated PD (APD). For these reasons, we assessed PD use worldwide by compiling data from multiple sources over a 12-year period. We examined the trends in PD use across developing and developed nations, focusing on crude numbers, prevalence per million population, and the proportion of dialysis patients who received PD. We hypothesized an increasing PD prevalence in the dev...