The Beck Depression Inventory (BDI) is one of the most commonly used instruments to assess depression in persons with obesity. While it has been validated in normal and psychiatric populations, in obese populations, its validity remains uncertain. This study aimed to investigate the validity and reliability of the BDI-IA and BDI-II in severely obese bariatric surgery candidates.Consecutive new candidates at a bariatric surgery clinic were invited to participate in the study by their consulting surgeon. All candidates were assessed using the Structured Clinical Interview for DSM-IV Disorders (SCID-I); 118 completed the BDI-IA and 83 completed the BDI-II. Two hundred one patients (response rate, 88 %) participated in the study. The current sample (82 % female) had an average body mass index of 42.83 ± 6.34 and an average age of 45 ± 12 years.Based on the SCID-I, 54 candidates (26.9 %) met the criteria for a mood disorder, with 37 meeting the criteria for current major depressive disorder. Individuals diagnosed with a clinical mood disorder had significantly higher scores on the BDI (BDI-IA, 23.59 ± 9.69 vs. 12.76 ± 8.29; BDI-II, 22.93 ± 5.22 vs. 11.25 ± 8.44). Our results indicated that, as a screening tool for a clinical mood disorder, the BDI-II had an optimal cutoff of 13, with a sensitivity of 100 and specificity of 67.75.Results indicated that the BDI-IA should not be used as a tool to measure depressive symptomatology in obese bariatric surgery candidates. No cutoff was identified with adequate sensitivity and specificity, and over 20 % of patients were misclassified. As a screening tool for a clinical mood disorder, the BDI-II was adequate; however, prevalence rates were significantly overestimated.