Frequent assessment of eating disorder (ED) symptoms (e.g., on a weekly basis) may guide treatment planning in clinical services, and be an invaluable tool for improving clinical research. The aim of the present study was to evaluate the psychometric properties of a brief eight-item scale designed to assess ED behaviors during the preceding week (Eating Disorder Symptom List: EDSL). Cross-sectional data were collected in a non-clinical community sample (n = 406) and cross-sectional and longitudinal data were gathered in a clinical ED sample before and after treatment with Enhanced Cognitive Behavior Therapy for eating disorders (n = 47) and weekly during treatment with Radically Open Dialectical Behavior Therapy (n = 13). The EDSL showed acceptable to good internal consistency (α = 0.72-0.82) and test-retest reliability (r = 0.88). Convergent and divergent validity was satisfactory. Also, the EDSL was sensitive to change and could detect changes between before and after treatment, as well as on a weekly basis. We conclude that the EDSL is a brief scale entailing little patient burden, and that initial analyses of the scale provide preliminary evidence of satisfactory psychometric properties. The scale can be used for repeated measures in ED treatment studies and clinics to assess change or absence of change during treatment.