The main goal of this research was to examine the effect of written exposure on GAD-related symptoms in high worriers. Thirty (30) nonclinical high worriers were randomly assigned to either a written exposure condition ( n = 15) or a control writing condition ( n = 15). Participants in the exposure condition wrote emotional descriptions of feared outcomes, whereas participants in the control condition wrote objectively about a neutral, hypothetical situation. All participants wrote for 30 minutes each day over five consecutive days. Self-report measures were used to assess worry, GAD somatic symptoms, depression, and intolerance of uncertainty at four time points during the study: pretest, posttest, and 1- and 2-week follow-ups. Given that exposure-based treatments are effective for GAD and related symptoms (e.g., Borkovec, Wilkinson, Folensbee, & Lerman, 1983; Dugas et al., 2003), we hypothesized that the exposure group would show greater decreases in symptoms (i.e., worry, GAD somatic symptoms, and depression) than would the control group. Further, considering that changes in intolerance of uncertainty generally precede changes in worry over the course of treatment for GAD (Dugas & Ladouceur, 2000), we expected that intolerance of uncertainty scores would predict subsequent symptom scores in the exposure group. Using hierarchical linear modeling (HLM), we found that all symptoms significantly decreased over time in the written exposure group (although GAD somatic symptoms also decreased in the control group). Moreover, intolerance of uncertainty scores predicted subsequent scores on all symptom measures in the experimental group, whereas worry and depression scores predicted subsequent intolerance of uncertainty scores in the control group.