This study is concerned with online learners\' \'flow\' experiences. On the basis of Csikszentmihalyi\'s theory of flow, flow was put forward as a complex, multimentional, and reflective construct composing the elements of \'enjoyment\', \'telepresence\', \'focused attention\', \'engagement\', and \'time distortion\' on the part of learners. A flow model was formulated with regard to virtual-class environment in a traditional university context, comprised with flow antecedents, flow, and flow consequences. After developing a Cyber-class Flow Measure(CFM), we surveyed 525 undergraduate students engaged in virtual-classes in order to examine the empirical relationships between measured flow antecedents, flow, and class satisfaction. The analysis of the data showed that 1) students\' perceptions of their level of skill-competence and those of task challenge specific to each course are critical to determining the level of flow, 2) flow is a significant predictor of class satisfaction, and 3) other than the flow, individual differences such as gender and having a clear goal can also make a big difference in the level of flow in a virtual-class context. These findings were discussed along with implications for bringing up a Computer-Mediated Environment(CME) more conducive to flow and learning.