Recent research has documented the unusually high rates of incarcerated women’s serious mental illness (SMI) and substance use disorders (SUD). Complicating these high rates is the high comorbidity of SMI with SUD and trauma histories. Yet, incarcerated women have significantly less access to treatment and health services while incarcerated than men. We used data from a multi-site, multi-method project funded by the Bureau of Justice Assistance (2011–2012) to determine the risk profile of women in jail (n=491) with a current co-occurring SMI (i.e., major depressive disorder, bipolar disorder, schizophrenia spectrum disorder)and SUD (i.e., abuse, dependence). The study spanned multiple geographic regions, and structured diagnostic interviews were used to understand better the women that comprised this vulnerable population. One-in-five of the women had a current co-occurring disorder (CCOD). The findings revealed that significantly more women with a CCOD had been exposed to violence and were exposed to drugs at a younger age. Further, about one-third of women with a CCOD had received no treatment from a health care professional in the past year, demonstrating a substantial unmet need. We conclude that investing in mental and behavioral health care in jails is critical to the health and safety of women as well as the communities to which they return.