We described sexual transmission behaviors and serodiscordant partnerships among an online sample of HIV-positive men who have sex with men (N = 416) in Asia. High rates of unprotected anal intercourse (74.8%), serodiscordant partnerships (68.5%), and unprotected sex within serodiscordant partnerships (∼60.0%) were reported. Increased number of partners, meeting partners on the Internet, drug use before sex, and not knowing one's viral load were associated with unprotected anal intercourse. Efforts to develop and scale up biomedical and behavioral interventions for HIV-positive men who have sex with men in Asia are needed.