Case-based learning (CBL) is an approach that uses clinical case activities in the classroom to engage students and encourage a deeper understanding of scientific concepts. Anatomy and Physiology (A&P) is a course that many students take as a prerequisite for admission to professional health schools. This study investigated the effect of CBL in facilitating clinical reasoning skills (CRS) in undergraduate A&P instruction. Undergraduate students from two classes taught by the same instructor participated in the study. One class (experimental group, n = 24 ) was taught with the CBL approach, and the other class (control group, n = 24 ) was taught without CBL. Quantitative data collected for this study were scores on the pretest and posttest clinical reasoning problem (CRP) instrument about the central nervous system, autonomic nervous system, and special senses. A 2 x 2 (CBL vs. No CBL x Pre-Posttest) mixed-model analysis of variance (ANOVA) was performed for each of the three systems with the scores on CRP as a dependent variable. Nine students were selected for interviews from the control and experimental groups based on their CRP assessments. Interviews were conducted after the completion of each CRP assessment, and content analysis was performed for the interview data. Analysis of the quantitative data revealed an increase in mean scores from pretest to posttest for those in the experimental group but a decrease in mean scores from pretest to posttest for those in the control group. Scores on special senses revealed a significant group x time interaction effect. Analysis of the interviews revealed that students in the experimental group utilized A&P concepts while reasoning through the CRP assessments. These results suggest that CBL may help facilitate CRS. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]