Seeking sexual partners online is associated with sexual risk-taking among men who have sex with men (MSM), but it is not well understood how this use of the Internet is implicated in potential sexual risks. The present study explores whether fantasizing about unprotected anal intercourse (UAI) during online chatting is associated with UAI with partners met online. An online survey of 2058 MSM in France included assessments of UAI with partners met online, responses to erotic chatting about UAI, intentions to use condoms, attitudes regarding UAI, practicing UAI with casual partners, alcohol and drug use with sex and biographical characteristics. While intentions to use condoms with casual partners were high, one-third (32.1%) of respondents reported UAI with partners met online. Responding positively to online chatting about UAI was significantly associated with UAI with partners met online, controlling for intentions, attitudes, behavior and biographic characteristics. These findings suggest that, while MSM may not go online to seek UAI, some engage in online fantasizing about UAI that is associated with possible sexual risk-taking. This speaks critically to the assumption that online fantasizing has no behavioral implications, and underscores the importance of human immunodeficiency virus prevention that addresses the dynamics of online chatting.