With evolutionary biology relatively recently introduced into the South African school curriculum, the need arose to explore practising teachers' knowledge of the subject. A number of anticipated as well as unanticipated cognitive and affective barriers to the understanding of evolutionary biology were identified from a questionnaire with open-ended items and administered at the start of a short learning programme on evolution education. The questionnaire was face validated and piloted. Teachers were conveniently sampled and comprised all course participants (n = 57). Responses to the questions were analysed using inductive and deductive coding. These codes were organised into themes, guided by the research question. These themes indicated poor content knowledge, essentialist and teleological reasoning, creationist objections and a perceived racist agenda to the teaching of this subject.