Information on sexual networking between different ethnic groups, in particular between Chinese and non-Chinese, is scarce. This study compared patterns of sexual behaviour and determinants of unsafe sexual behaviours amongst the Chinese and non-Chinese residents of Hong Kong. Of the 2,060 respondents (2060/4157; 50% response rate), 73% identified themselves as being ethnic Chinese. Overall, having a non-regular partner was more common amongst the non-Chinese (36%) than the Chinese (17%) respondents. Chinese people who were at increased risk of having had sex with a non-regular partner included social hygiene clinic attendees and airport travellers, males and ever smokers. For non-Chinese this was inconsistent condom use and being aged 18-45. Predictors of inconsistent condom use for Chinese included being aged 18-45, never having been married, and having had sex with non-regular partners; for non-Chinese the predictors were being aged 18-45, having had sex with non-regular partners and being unafraid of AIDS. We conclude that there are similarities and differences in sexual risk-taking behaviours between Chinese and non-Chinese residents in Hong Kong. To maximize potential public health benefits, behavioural interventions should be designed to address the different risk profiles of Chinese and non-Chinese populations separately.