Student performance in and attitudes towards oral and written assessments were compared using quantitative and qualitative methods. Two separate cohorts of students were examined. The first larger cohort of students (n = 99) was randomly divided into "oral" and "written" groups, and the marks that they achieved in the same biology questions were compared. Students in the second smaller cohort (n = 29) were all examined using both written and oral questions concerning both "scientific" and "personal development" topics. Both cohorts showed highly significant differences in the mean marks achieved, with better performance in the oral assessment. There was no evidence of particular groups of students being disadvantaged in the oral tests. These students and also an additional cohort were asked about their attitudes to the two different assessment approaches. Although they tended to be more nervous in the face of oral assessments, many students thought oral assessments were more useful than written assessments. An important theme involved the perceived authenticity or "professionalism" of an oral examination. This study suggests that oral assessments may be more inclusive than written ones and that they can act as powerful tools in helping students establish a "professional identity". (Contains 2 figures.)