A randomized trial was conducted of two different self-help programs for panic disorder (PD) on the Internet. After confirming the PD-diagnosis with an in-person structured clinical interview for DSM-IV (SCID) interview 22 participants were randomized to either applied relaxation (AR) or a multimodal treatment package based on cognitive behavioral therapy (CBT). Overall, the results suggest that Internet-administered self-help plus minimal therapist contact via e-mail has a significant medium to large effect (Cohen's d=0.71 for AR and d=0.42 for CBT). The results from this study generally provide evidence to support the continued use and development of Internet-distributed self-help programs.