This analysis aimed to determine whether the relationship between a history of arrest and unprotected anal sex (UAS) is the same for Black/Latino gay, bisexual, and other young men who have sex with men (YMSM) as compared to White/Asian/Pacific Islander (API) YMSM in New York City (NYC). Baseline audio-computer-assisted self-interview (ACASI) and interviewer-administered survey data from a sample of 576 YMSM aged 18-19 years old who self-reported being HIV-negative were analyzed. Data included history of arrest and incarceration as well as UAS in the past 30 days. Race/ethnicity was an effect modifier of the association between arrest and UAS among YMSM: White/API YMSM with a lifetime arrest history were more than three times as likely to report UAS, and Black/Latino YMSM with a lifetime history of arrest were approximately 70 % less likely to report UAS as compared with White/API YMSM with no reported arrest history. Race/ethnicity may modify the relationship between arrest and sexual risk behavior because the etiology of arrest differs by race, as partially evidenced by racial/ethnic disparities in police stop, arrest, and incarceration rates in NYC. Arrest could not only be an indicator of risky behavior for White/API YMSM but also an indicator of discrimination for Black/Latino YMSM. Further research is needed to assess whether the differential associations observed here vis-à-vis race/ethnicity are robust across different populations and different health outcomes.