The objective of this cross-sectional, observational study was to compare the dietary history and the 7-day record method to assess dietary habits in obese women. The second goal was to investigate whether eating behavior characteristics influence self-reported dietary intake. The study took place at the Obesity Outpatient Clinic, University Hospital Gasthuisberg, Leuven, Belgium. Subjects were 137 obese women with a mean age of 40 +/- 12 years and a mean body mass index of 38.2 +/- 6.0 kg/m2. Dietary intake was assessed both by the dietary history and by the 7-day record method. Resting energy expenditure was measured by continuous indirect calorimetry. Physical activity level was estimated using the Baecke questionnaire. To study different aspects of eating behaviour, the "Dutch Eating Behaviour Questionnaire" was used. Absolute energy intake, as assessed by the 7-day record, was consistently lower than with the dietary history method. Sixteen percent of the obese women were overreporters while 66% clearly underreported energy intake, using dietary history as standard method. Restrained eating was associated with underreporting, while all aspects of emotional and external eating behavior were significantly higher in the group of overreporters. No relationship could be observed between the degree of underreporting and age, body weight or body mass index. Energy intake, as assessed by the dietary history method, correlated better with measured energy expenditure in obese subjects than the 7-day record. Eating behavior characteristics influence the accuracy of self-reported dietary intake in obese women.