Sixty-four individuals with social phobia (social anxiety disorder) were assigned to a multimodal cognitive-behavioral treatment package or to a waiting list control group. Treatment consisted of a 9-week, Internet-delivered, self-help program that was combined with 2 group exposure sessions in real life and minimal therapist contact via e-mail. Results were analyzed on an intention-to-treat basis, including all randomized participants. From pre-to posttest, treated participants in contrast to controls showed significant improvement on most measured dimensions (social anxiety scales, general anxiety and depression levels, quality of life). The overall within-and between-groups effect sizes were Cohen's d = 0.87 and 0.70, respectively. Treatment gains were maintained at 1-year follow-up. The results from this study support the continued use and development of Internet-distributed, self-help programs for people diagnosed with social phobia.