Computer-aided assessment (CAA) has been used at a university with one of the largest mathematics and engineering undergraduate cohorts in the UK for more than ten years. Lecturers teaching mathematics to first year students were asked about their current use of CAA in a questionnaire and in interviews. This article presents the issues that these lecturers faced as they made use of this assessment tool. Lecturers explained how they attempted to overcome these issues. The findings show that while the lecturers were happy to use the CAA system because it is efficient and timesaving, there were concerns that it might not always be beneficial for students. The bases for lecturers' concerns were that some students developed tendencies to depend on the feedback to complete assessments and to develop procedural, context-dependent strategies for solving problems.