IDDM and eating disorders are common conditions in young women. Whether a specific association exists between these two disorders remains controversial. Some studies have suggested an increased incidence of eating disorders in young women with IDDM, whereas others have not detected such an increase. These differences may be attributable, at least in part, to methodological issues in study design, measurement tools, and relatively small sample sizes. Whether the prevalence of eating disorders in IDDM is increased will be resolved only by larger studies that use standardized diagnostic interviews. We suspect that certain aspects of IDDM and its management may trigger the expression of an eating disorder in susceptible individuals. Required dietary restraint and weight gain related to diabetes management are the factors most likely to be implicated. Eating disorders are relatively common in young women with IDDM and may contribute to impaired metabolic control with hypoglycemia and DKA, and to long-term microvascular complications of diabetes. Omission or reduction of required insulin, an extremely common means of weight control in these young women, is likely an important factor in this regard. Further research is required to determine more precisely the relationship between IDDM and eating disorders, and the effects of eating disorders on metabolic control and chronic complications of IDDM.