This study reports on the development and initial psychometric properties of the Children’s Saving Inventory (CSI), a parent-rated measure designed to assess child hoarding behaviors. Subjects included 123 children and adolescents diagnosed with primary Obsessive–Compulsive Disorder (OCD) and their parents. Trained clinicians administered the Children’s Yale-Brown Obsessive–Compulsive Scale (CY-BOCS), items assessing Family Accommodation and the Clinical Global Impressions—Severity index. Parents completed the CSI, Child Obsessive–Compulsive Impact Scale (COIS)—Parent Version and Child Behavior Checklist. Youth completed the COIS—Child Version, Obsessive–Compulsive Inventory Child Version (OCI-CV), Multidimensional Anxiety Scale for Children, and Children’s Depression Inventory—Short Form. A four factor solution was identified; factors were named Discarding, Clutter, Acquisition, and Distress/Impairment. Internal consistency for the CSI Total and factor scores were good. One-week test–retest reliability (n = 31) from a random subsample was excellent. Known groups validity was supported vis-à-vis higher CSI scores for those endorsing hoarding on the CY-BOCS Symptom Checklist. Convergent and discriminant validity was evidenced by weak relationships with OCI-CV Checking and Contamination factors but strong relationships with the OCI-CV Hoarding factor and with hoarding obsession/compulsions on the CY-BOCS. These findings provide initial support for the reliability and validity of the CSI for the assessment of hoarding behaviors among youth with OCD. Future studies are needed to extend these findings to non-OCD samples of youth.