We developed an instrument that allows instructors to conduct a comprehensive evaluation of the quality of Web-based courses. Development and validation of the instrument involved four phases. In Phase I, an instrument was developed based on survey results from students and instructors of Web-based courses and an extensive literature review. In Phase II, the instrument was placed on the World Wide Web to collect data. Phase III was a validity study using the data collected in Phase II. In Phase IV, the instrument was revised using feedback from the first three phases.