ABSTRACT: Emerging adulthood (EA) is a developmental period marked by unique challenges that affect health including burgeoning occupational, relational, and financial stability; and increased risk taking in terms of sexual behavior(s) and substance use. Data were collected from 296 HIV-uninfected sexual minority men with childhood sexual abuse (CSA) histories. We analyzed baseline assessment data from a multisite randomized controlled trial that tested the efficaciousness of an experimental psychosocial treatment and examined vulnerabilities known to be linked with CSA. Our analyses compared EA sexual minority men, aged 18-29, with older sexual minority men (OSMM) on posttraumatic stress disorder (PTSD) and other mental health and substance use outcomes. We found higher odds of PTSD, odds ratio (OR) = 0.57, 95% CI [0.33, 0.96]; panic disorder or panic disorder with agoraphobia, OR = 0.36, 95% CI [0.16, 0.85]; and cocaine use, OR = 0.50, 95% CI [0.25, 0.97], among OSMM and higher odds of alcohol intoxication, OR = 5.60, 95% CI [3.20, 9.82]; cannabis use, OR = 3.09, 95% CI [1.83, 5.21]; and non-HIV sexually transmitted infections, OR = 3.03, 95% CI [1.29, 7.13], among the EA men. These results present a complex picture of health risks among sexual minority men in general and EA sexual minority men in particular. HIV seroconversion linked health risk behaviors, among sexual minority men, may be better addressed via increased attention to treating trauma and comorbid mental health and substance use problems using evidence-based psychosocial assessments and integrated treatment platforms that are tailored to this population.