The identification of students with the potential to succeed in mathematics- and science-based study despite previous educational disadvantage is a critical issue currently facing many South African higher education institutions. The possible use of school-leaving examination (Matric) results and/or scores on specially developed aptitude tests for the selection of disadvantaged students was investigated during a four year UNIFY Selection Research Project. UNIFY is a mathematics and science foundation year programme at the University of the North, intended specifically for disadvantaged students from previously black-only educational systems. The research results show that both Matric results and aptitude tests have predictive validity for student performance in UNIFY. Matric results add significantly to the predictive validity attained by the UNIFY selection tests. No significant predictive bias against home and school background is found for the UNIFY student group for either Matric results or aptitude tests. © 2003 Elsevier Science Ltd. All rights reserved.