As the Personal Digital Assistant (PDA) user population continues to expand, there is a need to design more useful devices and applications to facilitate the utilization of PDAs. We conducted a structured interview study to examine PDA usage and non-usage patterns among physicians. The purpose of this descriptive study was to identify the barriers that impede physicians in their PDA use. A data collection tool was developed to record: 1) how physicians use their PDAs, 2) functions and applications used, 3) functions and applications not used, 4) reasons and examples of why physicians don't use PDAs for those functions, and 5) the recall of specific incidents of PDA usage using Critical Incident Technique (CIT). Interview data were transcribed and analyzed. Study findings and how those barriers can be addressed are discussed.