Interest in the educational use of information and communication technologies (ICT) in higher education is increasing. For successful implementation, it is important to know students' attitudes and reservations and how they can be positively influenced. The objective of the present study was to examine possible attitudinal changes towards computer-based assessment (CBA) in students, after undergoing one such assessment. A web-based mock examination was provided to all fourth year medical students at Leipzig Medical School in 2008 and 2009. Before and after the web test, students were asked to document their agreement with statements concerning CBA. A large number of students made use of the offered web-based assessment. 383 participants could be analysed for the pre-post comparisons. The majority of the students rated their computer self-efficacy as high. In summary, students' attitudes towards CBA in higher education tended to be positive. Gender differences seemed to be substantially influenced by differences in computer self-efficacy and were reduced considerably after only one practical experience. The actual experience had a positive influence on attitudes towards CBA. Nevertheless there were strong reservations about technical problems influencing the test performance when used for summative assessment. These concerns should not be ignored when trying to implement CBA. Optional formative CBA, perhaps early in higher education, seems to be a promising possibility of attracting students to computer- or web-based examination and learning methods, and may be a useful component of a successful implementation strategy. (Contains 3 tables.)