Many current measures of eating disorder (ED) symptoms have 1 or more serious limitations, such as inconsistent factor structures or poor discriminant validity. The goal of this study was to overcome these limitations through the development of a comprehensive multidimensional measure of eating pathology. An initial pool of 160 items was developed to assess 20 dimensions of eating pathology. The initial item pool was administered to a student sample (N = 433) and community sample (N = 407) to determine the preliminary structure of the measure using exploratory and confirmatory factor analyses. The revised measure was administered to independent samples of patients recruited from specialty ED treatment centers (N = 158), outpatient psychiatric clinics (N = 303), and students (N = 227). Analyses revealed an 8-factor structure characterized by Body Dissatisfaction, Binge Eating, Cognitive Restraint, Excessive Exercise, Restricting, Purging, Muscle Building, and Negative Attitudes Toward Obesity. Scale scores showed excellent convergent and discriminant validity; other analyses demonstrated that the majority of scales were invariant across sex and weight categories. Eating Pathology Symptoms Inventory scale scores had excellent internal consistency (median coefficient alphas ranged from .84-.89) and reliability over a 2- to 4-week period (mean retest r = .73). The current study represents one of the most comprehensive scale development projects ever conducted in the field of EDs and will enhance future basic and treatment research focused on EDs.