Business-to-Consumer (B2C) websites are widely used nowadays. The success of B2C websites could be directly affected by their usability. A survey study was conducted to investigate and prioritize the importance of 19 usability considerations with respect to users’ purchase intentions on B2C websites. Responses from 287 web users were obtained and analyzed. Factor analysis reveals that users’ purchase intention on B2C websites is affected, in descending order of importance, by the following five usability factors: trustworthiness, shopping support, information access efficiency, ease of comprehension and hedonic quality. Some interesting differences among ethnic (American and Chinese), gender (men and women) and age (18 to 25 and 26 to 35) groups are also observed. Prioritized usability considerations can help website design teams plan their development efforts.