ABSTRACT: Importance:Despite favorable national trends in the incidence of end-stage renal disease (ESRD) from 2008 to 2011, ESRD incidence has been increasing recently, and less than 10% of patients with ESRD start renal replacement therapy with peritoneal dialysis (PD) in the United States. Given known and potential advantages of PD over hemodialysis, the Kaiser Permanente Northern California integrated health care delivery system implemented a program to expand use of PD. Objectives:To describe the system-level approach to expansion of PD use and temporal trends in initiation and persistence of PD and its associated mortality. Design, Setting, and Participants:This retrospective cohort study included adult members of a large integrated health care delivery system in Northern California who initiated chronic dialysis therapy from January 1, 2008, through December 31, 2018. Data were analyzed from March 1, 2018, through May 31, 2019. Exposure:From 2008 to 2018, Kaiser Permanente Northern California implemented a multidisciplinary, system-wide approach to increase use of PD that included patient and caregiver education, education and support tools for health care professionals, streamlined system-level processes, monitoring, and continuous quality improvement. Main Outcomes and Measures:Temporal trends in the proportion of patients starting chronic dialysis with PD vs hemodialysis compared with national trends. Secondary outcomes included persistence of PD at 1 year in those initiating it and standardized 1-year mortality rates in those initiating PD or hemodialysis. Results:Among 13 500 eligible health plan members in the study population (7840 men [58.1%] and 5660 women [41.9%]; mean [SD] age, 64.3 [14.4] years), initiation of PD increased from 165 of 1089 all new dialysis patients (15.2%) in 2008 to 486 of 1438 (33.8%) in 2018, which was substantially higher than national trends (6.1% in 2008 and 9.7% in 2016). Among the 2974 patients who initiated PD from 2008 to 2017, 2387 (80.3%) continued PD at 1 year after initiation, with a significant increase in age-, sex-, and race-standardized rates from 2008 (69.1%) to 2017 (84.2%). Age-, sex-, and race-standardized 1-year mortality for patients receiving PD and hemodialysis did not change significantly across this 10-year period (17.3% to 15.5% for hemodialysis, P = 0.89 for trend; and 5.5% to 7.3% for PD, P = 0.12 for trend). Conclusions and Relevance:This study suggests that large-scale expansion of PD is feasible using a multidisciplinary, integrated, coordinated care approach; we believe these findings represent a national opportunity to improve outcomes for patients with advanced kidney disease.