In South Africa under apartheid, higher education was unavailable to a large segment of the population. Many who enrol for an undergraduate degree today are thus mature students or 'adult learners' 25 years or older who are in full-time employment. Since these students learn differently from their younger peers, institutions need to know what factors influence their academic performance, so as to target interventions and support services accordingly. Performance in the first year is a significant predictor of final year performance. We explored the role of cognitive abilities and personal competencies in the academic performance of 207 adult education students enrolled in the first year of an undergraduate degree at a Business School in South Africa. We found that for these adult learners cognitive abilities, particularly verbal reasoning, were a more consistent predictor of academic success than personal competencies.