This article examines the role of mental health, substance use, and comorbidity in relation to time to reincarceration. Our study included all people released from provincial correctional facilities in British Columbia, Canada, from 2012 through 2014 ( N = 13,109). Using data from a mental health screening tool, we examined the relationship between four diagnostic groups (mental health needs alone, substance use disorders alone, co-occurring disorders, and no disorders) and time to reincarceration over a 3-year follow-up period. We found that people with co-occurring disorders and substance use disorders were at substantially elevated risk of reincarceration compared with those with no disorders or mental health needs alone. Mental health needs alone was not significantly associated with reincarceration after adjusting for covariates. Correctional, health, and social services must work synergistically to improve health and criminal justice outcomes, particularly for people with substance use and co-occurring disorders.