e18125 Background: The 2010 Dependent Coverage Provision (DCP) of the Affordable Care Act (ACA) allowed young adults to remain on their parents' health insurance until age 26 years (y), whereas pre-DCP the cut-off varied, but was most often 18 y. Our objective was to compare rates of insurance disenrollment among patients with cancer who were DCP-eligible compared to those who were not. Methods: A retrospective cohort from the OptumLabs Data Warehouse, which includes claims data for privately insured enrollees in a large US health plan, was used. Patients born between 1982-93 diagnosed with cancer between 2000-15 were included. In the Recent Cohort, patients who turned 19 in 2010-12 (who were always eligible to stay on parents’ insurance) were matched to patients who turned 19 in 2007-09 (who were not protected by the DCP when they turned 19). Sensitivity analyses paired patients in an Earlier Cohort, who turned 19 (in 2001-03 and 2004-06), none of whom were eligible for the DCP when they turned 19. Patients were matched on cancer type, diagnosis date, and additional clinical characteristics. Using a time to loss of coverage analysis (defined as > 90 d interruption in insurance enrollment), hazard ratios (HR) were calculated using Cox proportional hazards models. Difference-in-difference between pairs from the Recent and Earlier cohorts was evaluated. Results: Of the 3,013 patients who turned 19 in 2010-12, 2,829 were matched. Median time to disenrollment was 26 months (m) compared to 22 m among patients who turned 19 in 2007-09 (HR 0.88, 95% CI 0.81-0.95, p = 0.0009). In the 4,489 pairs of patients who turned 19 between 2001-06, median time to disenrollment was 20 m among both the younger and older patients in the pair (p = 0.047). In grouped analyses, the difference-in-difference between the Recent and Earlier sets of pairs displayed a 14% reduction in the hazard for losing coverage (p < 0.0001), favoring those who turned 19 after DCP became available. Conclusions: In pediatric cancer patients and survivors, a vulnerable population that needs continuous insurance coverage, these data suggest that the DCP of the ACA lowers the insurance drop-out rate.