Background: Exercise training may be especially helpful for patients with generalized anxiety disorder (GAD). We conducted a randomized controlled trial to quantify the effects of 6 weeks of resistance (RET) or aerobic exercise training (AET) on remission and worry symptoms among sedentary patients with GAD. Methods: Thirty sedentary women aged 18–37 years, diagnosed by clinicians blinded to treatment allocation with a primary DSM-IV diagnosis of GAD and not engaged in any treatment other than pharmacotherapy, were randomly allocated to RET, AET, or a wait list (WL). RET involved 2 weekly sessions of lower-body weightlifting. AET involved 2 weekly sessions of leg cycling matched with RET for body region, positive work, time actively engaged in exercise, and load progression. Remission was measured by the number needed to treat (NNT). Worry symptoms were measured by the Penn State Worry Questionnaire. Results: There were no adverse events. Remission rates were 60%, 40%, and 30% for RET, AET, and WL, respectively. The NNT was 3 (95% CI 2 to 56) for RET and 10 (95% CI –7 to 3) for AET. A significant condition-by-time interaction was found for worry symptoms. A follow-up contrast showed significant reductions in worry symptoms for combined exercise conditions versus the WL. Conclusions: Exercise training, including RET, is a feasible, low-risk treatment that can potentially reduce worry symptoms among GAD patients and may be an effective adjuvant, short-term treatment or augmentation for GAD. Preliminary findings warrant further investigation.