A greater understanding of implicit cognition can provide important information regarding the etiology and maintenance of psychological disorders. The current study sought to determine the utility of the Implicit Relational Assessment Procedure (IRAP) as a measure of implicit aversive bias toward spiders in two groups of known variation, high fear and low fear. The study also endeavored to ascertain the predictive validity of the IRAP in terms of real-life behavior by means of a Behavioral Approach Task (BAT). Results demonstrated that the IRAP can differentiate between two groups with known differences in relation to spider fear. Furthermore, these distinctions act as predictors for overt avoidance behavior with a live spider. (Contains 1 table, 2 figures and 7 footnotes.)