Background and Objective: Social determinants of health are strongly associated with an increased risk of contact with the criminal justice system, especially at a younger age. People who have had contact with the youth justice system are at increased risk of death from external causes such as homicide, suicide, and accidents, but their burden of non-communicable disease (NCD) mortality is still largely unknown. We aimed to characterise NCD mortality and identify its associated risk factors for NCD deaths in a large sample of young people with a history of youth justice contact.    Methods:This was a retrospective cohort of all young people charged with a criminal in Queensland, Australia, between June 1993 and July 2014 (N=49,011), aged 10-18 years at baseline and censored on 31 January 2017 or at death. Youth justice records were linked to adult correctional records and death records. We estimated crude mortality rates (CMRs) and standardised mortality ratios (SMRs) by age, sex, and Indigenous identification, and identified risk factors for NCD deaths using competing risk regression models.   Results: There were a total of 121 NCD deaths in the cohort, occurring at a median age of 26.8 years (interquartile range=22.7-31.8). The overall CMR from NCDs was 18.5 (95% Confidence Interval: 15.5-22.1) per 100,000 person-years, which was 67% (95%CI: 39-99) higher than in the general population of the same age and sex. Having two or more episodes of adult incarceration (compared to none) was a risk factor for NCD death (aHR=1.75, 95%CI: 1.15-2.64).   Conclusions: Youth justice contact might offer a window of opportunity to connect vulnerable young people — who may be less likely to engage with primary and preventative care due to the high prevalence of substance use disorders and unstable accommodation — with services, support and social networks that can facilitate timely access to health care.