A clinical practical course entitled “Medical interview practice at first outpatient visits” aimed at improving medical interview and diagnostic skills, was organized for fifth- and sixth-year dental students in the Oral Diagnosis and General Dentistry, Dental Hospital, Tokyo Medical and Dental University. Students conducted an initial interview and oral examination of new outpatients and made a diagnosis using the acquired information. Instructors used an evaluation form comprising a checklist and rating scale to assess the students. We investigated the changes in interview methods and diagnostic skills, following the students' initial medical interview, to help improve the educational methods and assessment techniques. The evaluation sheets used by the instructors for the first and last interviews of 112 students were examined. In addition, the adequacy of the checklist evaluation items for attaining course targets was considered. The sum score of the checklists increased significantly over time. The overall achievement rate for checklist items also improved significantly, but three items, which were related to the doctor-patient relationship and diagnosis, did not improve satisfactorily at the last interview. A more limited number of items related to explanations and the doctor-patient relationship, involved in attaining course targets, was observed. It was found necessary to reconsider educational strategies, especially for improving undergraduate students' diagnostic skills, because of the possibility that information obtained from interviews may not be appropriately utilized for diagnosis.