Human H5N1 highly pathogenic avian influenza (HPAI) infection is associated with intimate exposure to live poultry. Perceptions of risk can modify behaviors, influencing actual exposure. However, greater hazard is not necessarily followed by perception of greater risk and more precautionary behavior because self-serving cognitive biases modulate precautionary and hazardous behaviors. We examined risk perception associated with avian influenza. A total of 1,550 face-to-face within-household interviews and 1,760 telephone interviews were derived to study avian influenza risk perception and live poultry use in Guangzhou and Hong Kong, respectively. Chi-square and Mann-Whitney tests assessed bivariate associations and risk distributions, respectively, and fully adjusted multivariate logistic models determined independent risk associations. Relative to Hong Kong, perceived "generalized" risk from buying live poultry (GZ, 58%, 95% confidence interval 55-60% vs. HK, 41%, 39-43%; chi(2)= 86.95, df = 1, p < 0.001) and perceived self/family risk from buying (z =-2.092, p = 0.036) were higher in Guangzhou. Higher perceived "generalized" risk was associated with not buying live poultry (OR = 0.65, 0.49-0.85), consistent with the pattern seen in Hong Kong, while perceived higher self/family risk was associated with buying ("likely/very likely/certain" OR = 1.74, 1.18-2.59); no such association was seen in Hong Kong. Multivariate adjustment indicated older age was associated with buying live poultry in Guangzhou (OR = 2.91, 1.36-6.25). Guangzhou respondents perceived greater risk relative to Hong Kong. Buying live poultry was associated with perceptions of less "generalized" risk but more self/family risk. Higher generalized risk was associated with fewer live poultry purchases, suggesting generalized risk may be a useful indicator of precautionary HPAI risk behavior.