BackgroundHoarding disorder is typified by persistent difficulties discarding possessions, resulting in significant clutter that obstructs the individual's living environment and produces considerable functional impairment. The prevalence of hoarding disorder, as defined in DSM-5, is currently unknown.AimsTo provide a prevalence estimate specific to DSM-5 hoarding disorder and to delineate the demographic, behavioural and health features that characterise individuals with the disorder.MethodWe conducted a two-wave epidemiological study of 1698 adult individuals, originally recruited via the South East London Community Health (SELCoH) study. Participants screening positively for hoarding difficulties in wave 1, and who agreed to be re-contacted for wave 2 (n = 99), underwent in-home psychiatric interviews and completed a battery of self-report questionnaires. Current DSM-5 diagnoses were made via consensus diagnostic procedure.ResultsIn total, 19 individuals met DSM-5 criteria for hoarding disorder at the time of interview, corresponding to a weighted prevalence of 1.5% (95% CI 0.7–2.2). Those with hoarding disorder were older and more often unmarried (67%). Members of this group were also more likely to be impaired by a current physical health condition (52.6%) or comorbid mental disorder (58%), and to claim benefits as a result of these issues (47.4%). Individuals with hoarding disorder were also more likely to report lifetime use of mental health services, although access in the past year was less frequent.ConclusionsWith a lower-bound prevalence of approximately 1.5%, hoarding disorder presents as a condition that affects people of both genders and is associated with substantial adversity.