The chief concerns for antiretroviral therapy (ART) programs considering removal of CD4+ cell count thresholds for treatment are the increased incidence of ART-related adverse events. A nationwide observational cohort study was conducted among patients who initiated ART in 2012. We divided the eligible patients into three groups: an early ART group with a baseline CD4+ cell count of 500 cells/μL or greater, a standard ART group with a baseline CD4+ cell count between 350 and 499 cells/μL, and a late ART group with a baseline CD4+ cell count between 200 and 349 cells/μL. These patients were followed up to December 31, 2014 and observed for three outcomes: virological failure, treatment nonretention, or time to death. Patients who met the eligibility criteria numbered at 26,752. Out of all study participants, 20,827 participants were in late ART group, 4336 were in standard ART group, and 1589 were in early ART group. Patients in late ART group were more likely to become virally suppressed 12 and 24 months after treatment initiation than patients in early ART group [adjusted odds ratio (aOR) 0.81; 95% CI, 0.69–0.95 and aOR, 0.78; 95% CI, 0.65–0.94]. Treatment nonretention was also less likely to occur among patients in late ART group than early ART group 12 months after treatment initiation (aOR, 0.85; 95% CI, 0.75–0.96). Compared with early ART group, neither standard ART group nor late ART group had a statistically significant difference in the time-to-death analysis. Late ART initiates were more likely to be virally suppressed and retained on treatment than early ART initiates. The importance of treatment retention and adherence should be emphasized for high CD4+ patients newly initiated to ART therapy through education and counseling programs.