This study examined cancer knowledge, mental health and smoking in formerly incarcerated men. The Cancer-Health Research Study with Formerly Incarcerated Men in New York City used a cross-sectional research design to examine knowledge and cancer prevention (CKP) outcomes among 259 justice-involved males, ages 35-67. CKP was assessed using items from the National Cancer Institute's Health Information National Trends Survey. Psychological symptoms were examined using the Brief Symptom Inventory. Of the 259 men who completed the survey, 76% of the respondents self-reported as current smokers. Current smokers smoked between one and 40 cigarettes per day. The mean number of cigarettes smoked per day was 10.37 (SD = 6.76). Sixty-three percent (n=165) of the respondents underwent cancer-screening tests. CKP scores ranged from two to 28; the mean was 15.05 (SD=5.49), indicating that the men scored very low in terms of CKP. CKP was negatively associated with the number of cigarettes smoked per day, τ = -.13, p = .01; participants with high knowledge scores smoked less daily. These results have important implications for enhancing access to cancer-health education in justice-involved settings.