This study was performed to estimate the cost of long-term disability in people who have anorexia nervosa (AN) that live in the province of British Columbia (BC), Canada. Canada provides universal socialized health and welfare services, and each of the 10 provinces is responsible for its own funding. As the provincial government of BC does not categorize its disability payments by the cause of the disability, a survey was used to determine the rate of disability from AN. A sensitivity analysis was performed to assess the influence of variations on the yearly cost of disability in BC: the number of patients with AN was varied between 1.0 and 2.0% of the female and 0.05 and 0.1% of the male population; the percentage of patients with AN receiving disability payments was determined by the survey to be 35%; the cost of these payments was varied between the lowest and highest benefits a single person can receive from the BC provincial government; and finally, to allow for possible sampling bias and a possible lower prevalence of AN, the lower limit of the sensitivity analysis was derived by dividing the lowest estimate above by seven. The sensitivity analysis revealed that the total estimated cost of long-term disability in BC could be as low as $2.5 million (Canadian) or as high as $101.7 million per year, which is a cost of up to 30 times the total yearly cost of all tertiary care services for the treatment of eating disorders in BC. In view of this finding, an increase in funding is warranted for primary, secondary and tertiary prevention programs for AN in BC.