The prevalence of Obsessive-compulsive disorder (OCD) among older adults varies between .5% and 4.5%. OCD typically develops at a young age, and many clinicians consider the chances of successful treatment in older adults to be minimal based on the chronicity of their symptoms. To date, no randomized controlled trial have been conducted on the effectiveness of treatments for OCD in older adults. This case study describes a high intensive cognitive behavioral therapy (CBT) provided to a 72-year-old man with OCD. This CBT program includes psychoeducation, exposure and response prevention, and cognitive therapy. The treatment was provided by a team of 5 therapists over one week. The patient’s score on the Yale Brown Obsessive-Compulsive Scale decreased from 31 at the start of the treatment to 2 by the end of treatment, which is below the recommended cut-off for a clinical diagnosis. Secondary depressive symptoms, as assessed with the Inventory of Depressive Symptomatology Self-Report, decreased from 57 at the start of treatment, to 1 by the end of treatment, which indicates the absence of depressive symptoms. The treatment gains were maintained with persistent remission until the 18-month follow-up. This study highlights an effective high intensive CBT program for older adults with OCD and challenges the false assumptions that (a) psychological interventions are ineffective for older adults and (b) existing treatments are unsuited for older adults. Future research should investigate the effects of this program in large sample with sufficient power.