Because social workers routinely deal with complex, multifaceted problems that defy clear definition or resolution, educational efforts to prepare students for practice must intentionally target the skills necessary to engage in this type of reasoning. This study evaluated the influence of case -based instruction on MSW students' reflective judgment, an aspect of critical thinking that has been linked to the ability to reason through ill-structured problems. Although students' performance on case analysis papers and a standardized measure and did not develop consistently, differential patterns of improvement based on initial levels of cognitive complexity suggest the importance of tailoring assignments to students' beginning levels of reflective judgment. The author concludes with a wide range of recommendations for targeting developmental growth at the various stages of reflective judgment.