Childhood disintegrative disorder (CDD) is a rare condition characterized by distinct regression of developmental and behavioral functioning following a period of apparently normal development for at least 2 years. The purpose of this article is to present the developmental, behavioral, psychosocial, and medical histories of eight children who have been diagnosed with CDD in an attempt to advance the understanding of this rare disorder. Results indicate the average age of onset was 3.21 years. Three cases reported an insidious onset while two cases exhibited acute onset. Developmental and behavioral milestones were met at age appropriate times in each case and significant deterioration of formerly acquired skills and abnormalities in functioning were clinically present in all eight cases.