This research examined the impact of the length and format (video, audio or text) of instructional Web modules (segments of lectures) on information recall, persistence, perceived content difficulty, aesthetic appeal, and perceived module length. Twelve Web-based instructional modules with different formats and lengths were evaluated through an experiment with a balanced-incomplete block design. The study showed no difference in information recall between the different module lengths and formats; however, as module length increased, participants were more likely to not complete the modules. Systematic evaluations of module length along with its visual appearance gives us insight to understand important factors that need to be considered when designing Web-based distance learning environments.