Motivating learners to continue to study and enjoy learning is one of the critical factors in distance education. Flow theory is a useful framework for studying the individual experience of learning through using computers. In this study, I examine students' emotional and cognitive responses to distance learning systems by constructing two models to test the students' flow states. The first model examines the cause and effect of the flow experience when students use distance learning systems. The second model considers the impact of three types of interaction on the flow experience. A questionnaire-based field survey is used to test the two models. Data from 253 distance learning students are examined under each of the two models. The results from Model 1 indicate that flow theory works well in a distance learning environment. The results from Model 2 point out that learner--instructor and learner--interface have a positive relationship with flow experience, whereas learner--learner interaction has not shown a significant relationship with flow experience. (Contains 6 tables and 4 figures.)