Obsessive Compulsive Disorder (OCD) involves exaggerated or excessive worry about threatening and non-threatening stimuli coupled with impairing rituals believed to reduce anxiety. Autism Spectrum Disorders (ASD) are characterized by impairment in social and communicative activities as well as restricted and repetitive behaviors. Approximately 2% of children with ASD are also diagnosed with OCD. Although there is extensive research demonstrating the effectiveness of behavioral interventions for pediatric OCD, little is known about how effective these treatments are for children who have a dual diagnosis of OCD and ASD. This report describes a 12-year-old male with Autism who was treated successfully with cognitive behavioral therapy with exposure and response prevention. This case study provides initial support that cognitive-behavioral therapy is effective in symptom reduction for children with comorbid autism and OCD.