To provide an overview of empirical findings with regard to compulsive hoarding.A systematic literature search of medical and psychological journals was conducted using PubMed. Relevant publications from the reference lists and recent books were also identified and included.The article reviews the phenomenology, diagnosis, etiology, neurobiology, prevalence, conceptualization, and treatment of compulsive hoarding. Compulsive hoarding is characterized by excessive acquisition, difficulty discarding possessions, clutter that precludes activities for which living spaces where designed and it causes significant distress, family and socioeconomic burden. Neuropsychological studies and neuroimaging indicate dysfunction of the anterior cingulated cortex and other ventral and medial prefrontal cortical areas.Further research is required to resolve the controversy as to whether compulsive hoarding is characteristic of a subtype of OCD or an unique syndrome and to develop disorder specific treatments.