We investigate the association between temperament and character dimensions, on the one hand, and computerised neuropsychological test performance, on the other hand. Temperament and character dimensions were operationalised as scores on the subscales of the Temperament and Character Inventory (TCI), a 240-item measure that is based on the psychobiological theory of personality. Neuropsychological outcomes were measured on six computerised tests of executive functioning and abstract reasoning from the University of Pennsylvania Computerised Neuropsychological Test Battery (PennCNP). The executive and abstract reasoning tasks included a test of Motor Praxis (MPRAXIS), the Penn Abstraction, Inhibition and Working Memory Task (AIM), the Letter-N-Back (LNB2), the Penn Conditional Exclusion Task (PCET), the Penn Short Logical Reasoning Task (SPVRT) and the Short Raven's Progressive Matrices (SRAVEN). Results from this exploratory study yielded significant associations between neuropsychological performance and temperament and character traits. The temperament traits of Harm Avoidance and Reward Dependence were positively correlated with reaction time on the AIM and the SPVRT. The character dimension of Self-Transcendence was significantly associated with performance accuracy on the AIM and the temperament dimension of Novelty Seeking was inversely related to performance accuracy on the LNB2. These results confirm the importance of addressing the temperament and character correlates of neuropsychological performance in both clinical and non-clinical studies.Keywords: character; executive functioning; neuropsychology; personality; psychobiological theory; temperament Research (Ardila, 2005;Byrd, Sanchez, & Manly, 2005; De Bruin, De Bruin, Dercksen, & CilliersHartslief, 2005;Hsieh & Tori, 2007;Nell, 2007;Rosselli & Ardila, 2003;Shuttleworth-Edwards, Kemp, Rust, Muirhead, Hartman, & Radloff, 2004;Uzzell, 2007) has shown that neuropsychological test performance is influenced by an array of diverse variables such as socio-demographic (e.g. gender, age); socio-cultural (e.g. education, language); and ecological variables (e.g. verbal, nonverbal and performance content). Studies that focus on the relationship between personality and/or temperament and neuropsychological test performance are scant.For the purposes of this investigation, personality is operationalised using Cloninger's psychobiological theory of personality (Cloninger, Svrakic, & Przybeck, 1993). This theory proposes a comprehensive personality model based on the interaction between temperament and character. It postulates four temperament and three character dimensions. Harm Avoidance (HA), Novelty Seeking (NS), Reward Dependence (RD) and Persistence (P) are the temperament dimensions, which regulate automatic emotional reactions and are considered reflections of individual differences in percept based habits and skills (neuro-biological dimension). The dimension of behavioural activation (NS) reflects the tendency toward exhilaration/impulsivity in response ...