Background: Pediatric onset multiple sclerosis (MS) negatively affects cognitive function, mood and health related quality of life (HRQOL). We aimed to explore the cognitive, psychological and HRQOL impacts of pediatric MS on young adults and to explore the relationships between disability, disease duration, cognition, mood and HRQOL in this hypotheses generating study. Methods: Thirty-four young adults with pediatric onset MS at St. Michael’s Hospital in Toronto were included in this cross-sectional study (mean age 21.3 years, 56% female). Participants completed assessments of physical disability (Expanded Disability Status Scale (EDSS)), cognitive function (Symbol Digit Modalities Test (SDMT)), mood (Beck Depression Inventory II (BDI-II)), and HRQOL (Short Form Health Survey (SF-36v2)). Findings were compared to age- and gender- matched normative data. Results: Individuals with pediatric MS performed worse on the SDMT compared to normative data, with 53% demonstrating cognitive impairment. There was no difference in BDI-II scores from normative data, but 21% showed at least mild depression. There was a non-significant impairment in physical HRQOL compared to normative data. Decreased physical HRQOL was related to disability (EDSS), while mental HRQOL was related to depression (BDI-II). Conclusions: Young adults with pediatric MS have reduced cognitive function. Non-significant reductions in HRQOL may be partly attributed to physical disability and depression. These factors should be addressed in the care of adults with pediatric MS. Further studies including control groups and longitudinal design are needed to confirm these findings.