Objective: The present study explores the clinical effectiveness of an Internet-based cognitive behavioural treatment program for social phobia (the Shyness program) administered by a psychiatric registrar as part of standard clinical treatment at an outpatient mental health service (the Anxiety Disorders Clinic, St Vincent's Hospital, Sydney). Method: Seventeen individuals with social phobia were assigned to this 8 week clinician-assisted program. All patients had access to online lessons, homework assignments, an online discussion forum with other patients, and regular emails from the clinician. Both completer and intention-to-treat models were used in data analyses. Results: Fourteen (82%) patients completed all six lessons within the 8 weeks, and 11/17 (65%) completed post-treatment questionnaires. Mean within-group effect sizes (Cohen's d) for the two social phobia measures were 1.06 and 0.77, based on completer and intention-to-treat analyses, respectively. Data indicate that the procedure was acceptable to patients. Conclusions: These results indicate that the procedure was clinically effective when operated as part of standard clinical treatment. These results provide further support for the potential clinical utility of the Shyness program.