A highly pathogenic H5N1 strain of avian influenza (AI) has been confirmed in 420 human cases and has caused 257 deaths in the world starting from 2003. Using face-to-face interviews, our data were collected by utilizing a stratified sampling scheme following the distribution of gender and age in three major metropolitan areas in Taiwan, including Taipei, Taichung, and Kaohsiung. The questionnaire was designed to retrieve information including AI knowledge, risk perceptions, and behavioral changes of two types of consumers, primary shoppers and general consumers. In total, 501 primary shoppers and 505 general consumers completed the survey in June 2007 and were recorded for analysis. The empirical results show several interesting findings, especially, that risk perception and some socioeconomic characteristics such as age are the key factor which determines changes in purchasing behavior.