Background: Among the treatment options offered to patients with severe obesity are surgery and psychotherapy plus dieting. The treatment choice may reflect differences in the psychology of these patients. The objective was to assess the psychopathological differences between patients with obesity who choose surgery and those who choose non-surgical treatment to lose weight. Methods: 100 patients with obesity (50 in the non-surgical group [NS]; and 50 in the surgical group [S]; 41 women and 9 men in each group) completed the MMPI-2 and the EDI-2; for the latter, data from 21 S and 24 NS women were available. Comparisons were carried out through analysis of variance. Results: The NS group scored higher on the Pa (paranoia) and Pt (psychasthenia) scales of the MMPI-2 compared to the S group. No differences were found on the EDI-2; however, both groups scored higher on the drive-for-thinness and body-dissatisfaction scales, and the NS group scored higher on the bulimia and ineffectiveness scales. Conclusion: The MMPI-2 was able to distinguish between the NS and S groups, while the EDI-2 found significant eating-related psychopathology in both.