Students entering engineering programmes are typically expected to be competent in mathematics and science. Design competencies are seldom required. This research focuses on mathematics and investigates how concepts of mathematics may affect perceptions of design. Case studies, consisting of interviews and web-based material, reveal a range of concepts. Mathematics bestows its knowers an intellectual status. Some see mathematics as the gateway to engineering, paving the way to sound design; others see mathematics as a gatekeeper, denying entry to otherwise talented would-be engineers. Mathematics is frequently seen as favouring closed solutions. For some students, this means that mathematics provides an unambiguous, reliable means of evaluation; others see mathematics as the suppression of creativity and open-ended design. If design is to flourish, mathematics must cease to be the litmus test of engineering abilities, and design must be taught alongside mathematics, not in its wake. (Contains 3 notes.)