In this work we explored the hypothesis that variation in the gene encoding apolipoprotein E (ApoE) is a factor modifying general cognitive ability (g). A case control sample of 101 high g and 101 average g children was scored for ApoE genotypes and two variants in the transcriptional regulatory region of the gene (Th1/E47cs and -491 AT). No evidence of association between these polymorphisms and g was found. We conclude that variation at these loci is not a factor with a measurable impact on general cognitive ability in the healthy population.