This paper describes the first trial of danger ideation reduction therapy (DIRT) in an adolescent patient with severe, treatment resistant obsessive-compulsive disorder (OCD). This case study also represents the first published data on DIRT for any individual outside the Anxiety Disorders Clinic at the University of Sydney, where the treatment package was originally developed. KP was a 16-year-old girl with a 4-year history of obsessive-compulsive disorder. She was primarily concerned with contamination and presented with associated washing and avoidance behaviour. KP met Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association [APA], 1994) criteria for OCD, oppositional defiant disorder and major depressive disorder. She had also had previous diagnoses of attention-deficit/hyperactivity disorder and motor tics. KP had received considerable treatment for OCD prior to the current trial, including 12 months of outpatient treatment at the local community health centre, a 4-week inpatient admission to a private hospital in Sydney and a 16 week inpatient admission to Rivendell Adolescent Unit in Sydney. All previous treatments involved a combination of pharmacotherapy (clomipramine [up to 125mg[, sertraline [up to the 200mg], fluvoxamine [up to 200 mg], risperidone [up to 2.5 mg] and chlorpromazine [25-50 mg prn]), and attempts to administer exposure-based treatment. KP had failed to benefit from all previous treatment attempts. However, following 16 sessions of DIRT, KP experienced substantial improvement, approximating symptom-free status on all measures. Importantly, these improvements were maintained at 12-month follow-up. The DIRT package was also effective in reducing depression and anxiety scores on self-report measures over the follow-up period. There were no substantial differences between posttreatment and 12-month follow-up scores on any of the measures given.