There has been paucity of data regarding the secular trend of adverseoutcomesinperitonealdialysis(PD) as compared withhemodialysis(HD) inKorea. 96,596 patients who starteddialysisbetween 2004-2015 inKoreawere identified using the National Health Insurance Service database. The adjusted hazard ratio (HR) (95% confidence interval, CI) of PD over HD for mortality was 1.31 (1.27-1.36; P < 0.001) in the period of 2004-2007 and 1.21 (1.16-1.27; P < 0.001) in the period of 2008-2011. However, the hazard of PD over HD for mortality turned out to be insignificant in the period of 2012-2015. Similar trend was noted for nonfatal cardiovascular events (CVEs). In subgroup analysis, the hazard of PD over HD for mortality was evident, regardless of the status of age, diabetes, and comorbidity burden in 2004-2011. In 2012-2015, however, the hazard of PD over HD for mortality was insignificant when follow up was censored at one year, which became significant when follow up follow up was censored at three or five year. In conclusion, the mortality of PD over HD inKoreahas been significantly improved, a finding that was paralleled by the improved nonfatal CVEs.