The psychometric properties of the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) were investigated in 46 treatment-seeking youth, 7-15 years of age, who were diagnosed with an autism spectrum disorder (ASD) and exhibited obsessive-compulsive symptoms. The CY-BOCS Total score exhibited good internal consistency, with differing internal consistencies observed on the Obsession Severity scale (α = 0.86) and Compulsion Severity scale (α = 0.59). Good to excellent inter-rater reliability was observed for the CY-BOCS Total score and both Severity scales. Convergent and divergent validity of the CY-BOCS Total score and both Severity scales were satisfactory. Insight into obsessive-compulsive symptoms was moderately associated with the CY-BOCS Total score. The CY-BOCS demonstrated treatment sensitivity, demonstrating significant changes in obsessive-compulsive symptoms within a subsample of youth receiving cognitive-behavioral treatment. Overall, the CY-BOCS demonstrated adequate psychometric properties and utility in assessing obsessive-compulsive symptoms in youth with ASD and clinically significant obsessive-compulsive symptoms.