Today's healthcare professional is challenged to stay current with increasingly complex therapeutic challenges, greater societal needs and expectations, and a public demand for the best possible care. Professional learning opportunities are needed to develop new knowledge, skills, or abilities to address specific matters encountered during professional practice. Professional learning opportunities must be relevant to a specific professional practice setting and promote change(s) in behavior, attitude, or practice before improvement in patient outcomes and population health can be realized. While much research has investigated professional learning specific to physicians, pharmacists have not been included. The purpose of this study was to identify how practicing pharmacists acquire professional learning. A theoretical model was developed to guide semistructured interviews of a stratified purposeful sample of practicing pharmacists in New Mexico. Pharmacists practicing in community, hospital and specialty settings in both rural and urban locations participated. Replication logic was used in this multiple case study to identify common factors that contribute to professional learning in practicing pharmacists. The study found no significant difference in (a) access or availability of resources, (b) environmental conditions, or (c) individual learning as a result of practice setting or location. Participants provided strong examples of self-directed learning, a professional pride in lifelong learning and a professional responsibility to stay competent in their practice setting. The factors identified in this study supported the underlying propositions of the theoretical model. The study increases the understanding of how practicing pharmacists acquire professional learning and can be operationalized in more comprehensive quantitative studies. This research contributes to the understanding of professional learning and can be used to develop educational methods that lead to enhancement and support of more effective professional learning. [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/en-US/products/dissertations/individuals.shtml.]