A comparative analysis of 51 case problems used in five problem-based pedagogical models was conducted to examine whether there are differences in their characteristics and the implications of such differences on the selection and generation of ill-structured case problems. The five pedagogical models were: situated learning, goal-based scenario, learning-by-design, problem-based learning and cognitive flexibility hypertext. The analysis revealed that while all case problems were authentic and multi-disciplinary, they varied across six themes for the pedagogical models examined: problem complexity, nature of problem topic, problem task, problem product, problem solving activity, and type of effort. The analysis also revealed that different kinds of case problems (e.g., dilemmas, design problems, case-analysis problems) are appropriate for different problem-based pedagogical models. These findings and their educational implications are described. (Contains 4 tables and 2 figures.)