OBJECTIVES: There is limited information on the prevalence of middle-aged women seeking specialized treatment for an eating disorder and whether middle-aged patients are significantly different from young-adult patients. This two-part study sought to identify changes in the past two decades in the prevalence of middle-aged (MA; 40+ years) and young-adult (YA; 18-39 years) women seeking treatment for an eating disorder (ED) and to identify differences and similarities between both groups. METHODS: For study 1, all unique female inpatient admissions from 1989 to 2006 were reviewed (n=1,040). For study 2, women admitted to any treatment level from January-May 2007 were compared, based on age at intake admission, on psychological questionnaires and factors relevant to an eating disorder. RESULTS: In study 1, the overall percent of MA women who presented for inpatient ED treatment increased significantly from an average of 4.7% (1989-2001) to an average of 11.6% (2002-2006). In study 2, at intake, MA women were more likely than YA to be married, be older at ED onset and report a longer duration of illness. Self-esteem, depression, anxiety, ED psychopathology, and BMI were not significantly different between groups. CONCLUSIONS: Findings indicate an increase in the prevalence of inpatient admissions among middle-aged women, but few differences between middle-aged and younger-aged women at treatment admission. However, the longer duration of illness among MA warrants in-depth investigation of factors related to resistance to seeking treatment and to existing treatments failing patients, and consideration of tailoring treatment to course of illness.