Women with bulimia nervosa (BN), dieters and non-dieting control participants were questioned about spontaneous imagery linked to concern with food and eating, weight and shape. The downward arrow technique was used to access any associated negative or core beliefs, which were examined for belief, distress and content. A semi-structured interview with open and closed questions was used. Negative self (core) beliefs were successfully accessed, and responses to the interview items had good test-retest and good inter-rater reliability. Patients with BN reported significantly more negative self (core) beliefs than those in the other two groups. Only a very small number of core beliefs about other people or the world in general were reported. Emotional belief ratings appeared to be higher overall than rational belief ratings. Patient's negative self-beliefs contained themes of "self-value", followed by "failure", "self-control" and "physical attractiveness", in descending order of frequency. The findings are discussed in relation to existing research, and implications for cognitive theories of bulimia nervosa and clinical practice are briefly discussed.