Recent theoretical models of social phobia suggest that targeting several specific cognitive factors in treatment should enhance treatment efficacy over that of more traditional skills-based treatment programs. In the current study, 195 people with social phobia were randomly allocated to 1 of 3 treatments: standard cognitive restructuring plus in vivo exposure, an "enhanced" treatment that augmented the standard program with several additional treatment techniques (e.g., performance feedback, attention retraining), and a nonspecific (stress management) treatment. The enhanced treatment demonstrated significantly greater effects on diagnoses, diagnostic severity, and anxiety during a speech. The specific treatments failed to differ significantly on self-report measures of social anxiety symptoms and life interference, although they were both significantly better than the nonspecific treatment. The enhanced treatment also showed significantly greater effects than standard treatment on 2 putative process measures: cost of negative evaluation and negative views of one's skills and appearance. Changes on these process variables mediated differences between the treatments on changes in diagnostic severity. (Contains 1 footnote, 3 tables and 1 figure.)