OBJECTIVE: Eating disorders (EDs) present across a broad age range, yet little is known about the characteristics and outcome of midlife patients compared to younger patients. Among patients seeking ED treatment who were stratified by age at initial assessment (IA), this study aimed to (1) discern sociodemographic and clinical differences, (2) determine outcome rates, and (3) identify predictors of poor outcome including death. METHOD: Participants [219 females (12 years or older, 94.1% Caucasian) who completed outcome assessment and 31 known decedents] were stratified by age at IA (<18 as youth, 18-39 as young adult, and ≥40 years as midlife adult). Analyses of variance and chi-square tests identified group differences; ordered logistic regression with stepwise selection identified factors predicting outcome. RESULTS: Midlife adults were more significantly compromised at follow-up compared to youths and young adults, including psychological and physical quality of life, ineffectiveness, interpersonal concerns, and general psychological maladjustment. Midlife adults had the highest rates of poor outcome or death; good outcome was achieved by only 5.9% of midlife adult compared to 14.0% of young adult and 27.5% of youth patients. Older age at IA, alcohol and/or drug misuse, endocrine concerns, and absence of family ED history predicted poor outcome or death. DISCUSSION: Midlife adults seeking ED treatment have more complex medical and psychological concerns and poorer outcomes than youths and young adults; further exploration is needed to improve treatment outcome. Specialized treatment focusing on quality of life, comorbid medical concerns, interpersonal connection, and emotion regulation is encouraged.