Many HRD staffs or decision makers believe that the primary benefit of web-based education is that costs can be distributed over a large number of students, resulting in economies of scale for educational institutions. It is assumed that large student enrollment would increase revenue and lower the cost per student and operating expenses. Moreover, it is known that web-based education can improve the quality of students\' learning experience through various types of online interaction and increasing access, and provide students with the access opportunities to a variety of multimedia resources and experts worldwide. Since many education institutions have adopted web-based education as their new form of delivery system for training, there is a growing need for cost-benefit analysis of web-based education compared to the conventional modes of delivery system. While previous studies have conducted costs and benefits analysis in conventional distance education setting, not much research has been conducted to assess cost-effectiveness of web-based education. This study aimed to investigate costs, benefits, and the methodologies of cost-benefit analysis in web-based education. Cost measures assessed in the study included capital and recurrent costs, production and delivery costs, prorated costs, fixed and variable costs, total costs and unit costs(average costs). Benefit measures assessed the study were course completion rate, learning outcome, interactivity, satisfaction, and intangible benefits. A value-based approach, a mathematical model approach, a comparative approach, a return on investment(ROI) approach, and an integrated approach were presented as methodologies for cost-benefit analysis of web-based education. Some studies examining costs, benefits, and cost-effectiveness of different forms of web-based education were also presented.