Internet self-reporting methods have opened new opportunities in research that focuses on women's physical activity. Understanding the strengths and limitations of this self-report Internet method is critical to conducting a feasible and effective Internet study. The purpose of this paper is to address consideration of the strengths and limitations for researchers undertaking physical activity studies of women utilizing the Internet self-reporting method (Tables 1 and 2). The analysis utilizes a cross-sectional Internet survey regarding physical activity among women. Five major strengths were found including (1) reciprocal communication, (2) reduction of data incompleteness, (3) accuracy of data entry, (4) convenience, and (5) confidentiality and anonymity. Five potential limitations were found including (1) low response rate, (2) recall bias, (3) validity and reliability of Internet-based instruments, (4) sample bias, and (5) indirect measurement. Information in this paper may serve as a future reference for researchers engaged in using a self-report Internet method to estimate women's engagement in physical activity.