In this study, we used data from Add Health Waves II and III to compare men who had been incarcerated to those who had not, and examined whether incarceration was associated with increased numbers of sexual partners and increased odds of concurrent partnerships. We used multivariate regression and propensity-score matching to compare sexual behavior of Wave III male respondents who had been incarcerated with those who had not, and compared sexual behavior at Wave II to identify differences in sexual behavior prior to incarceration. Incarceration was associated with an increased rate of lifetime sexual partnership, but this was attenuated by substance use. Criminal justice involvement was associated with increased odds of having partners who report concurrent partnerships, but no further increase was seen with incarceration. There were no significant sexual behavior differences prior to incarceration. These results suggest that the criminal justice system and substance use may interact to shape sexual behavior.