The aim of this study was to develop a tool for evaluating the quality of breast cancer information on the Internet from the perspective of patients and their families. A specific tool, Breast Cancer tool (BC tool), was developed based on the information needs of women with breast cancer and their families reported in the literature. The BC tool and other 3 generic tools (HON, IQ tool, Discern) were used to assess 40 breast cancer websites. The reliability and validity of each tool was examined and the time spent reviewing the websites was measured. The four tools were shown to have acceptable reliability (Cronbach's α>0.7), convergent validity, especially the BC tool which was capable of distinguishing whether a website offers sufficient information for women and their families. However, the BC tool took more time than the other tools to use, suggesting relatively low feasibility. The results of this study reinforce the importance of developing specific tools from perspectives of patients and their family members.