In a study to determine sampling differences between Internet sites, we obtained data on 353 men who have sex with men in Chinese gay chat rooms and through e-mail web sites. Respondents were approached by the investigator and agreed to fill out an anonymous questionnaire on their Internet use and sexual activity. All materials and contacts were in Chinese characters. Data indicated that there were few differences between the chat room and Internet samples, but that those using e-mail appear to be more isolated, more homosexually-identified (rather than bisexual), have more experience with casual partners on a number of sexual activities, and were less likely to carry condoms and to have safe sex. E-mail respondents were more likely to want to discuss HIV/AIDS prevention on a web site or other site. These data suggest that the two recruiting methods are largely comparable in respondent characteristics, but that e-mail respondents are likely to be more isolated and at higher HIV risk than chat room participants.