The authors describe the design and implementation of a new Web-based system that allows students to record important features of their clinical encounters during all 10 required clinical clerkships, document their learning experiences in six major competency domains, and generate detailed real-time reports for themselves and their clerkship directors. A new Web-based system, DMEDS (Dartmouth Medical Encounter Documentation System), accepts input from computers and PDAs. Its design permits students to describe their patients, learning sites, interactions with preceptors, and important aspects of their clinical encounters in all of our medical school's competency domains. Using a common format for all required clerkships, clerkship directors select specific items most relevant to their clerkships from a common menu and set learning targets for specific diagnoses and clinical skills. This new system was designed in the fall of 2003, tested in the spring of 2004, and implemented in all clerkships for the 2004 to 2005 academic year. During the first full academic year that DMEDS was used, students documented nearly 32,000 discrete student-patient-preceptor encounters, an average of between 21 and 120 clinical encounters per Year 3 clerkship. Highlights of the analysis of these initial data include the following: (1) insights into how educational targets are set, (2) the extent of site-to-site variation in clerkship experiences, (3) the epidemiology of patients' declining student involvement, and (4) student experiences in and understanding of the newer competency domains.DMEDS can be used in all clinical clerkships and can address student experiences in all competency domains. It provides substantial value to students, clerkship directors, preceptors, and medical school administrators. As secondary benefits, the authors found that DMEDS facilitates educational research and is readily adapted for use in residency and fellowship programs as well. Student feedback highlights the need to pay close attention to the time invested by students documenting their clinical encounters. Course directors must ensure that the benefits to students (such as knowledge of meeting learning targets and preceptors providing direct feedback to students) are transparent. Finally, for other schools contemplating the change to a competency-based curriculum with the use of a clinical encounter documentation system, the time required for both students and faculty to adopt and fully engage these major educational culture shifts seems to be at least several years.