The aims of the study were (1) to compare the defence style of patients with anorexia nervosa with that of patients with bulimia nervosa and of female controls; (2) to establish whether a link exists between childhood adversity and adult defence style in eating disorder patients. Twenty-six patients with restricting anorexia nervosa (RAN), 61 patients with bulimia nervosa (BN), 37 patients with bulimic anorexia nervosa or bulimia nervosa with a history of anorexia nervosa (BAN/BN-HistAN) and 88 female controls were given the short Defense Style questionnaire (Andrews, Pollock & Stewart, 1989). Eating disorder patients were asked about their childhood care using a semi-structured interview (Harris, Brown & Bifulco, 1986). Bulimia nervosa patients had a significantly less mature defence style than the other groups and like the BAN/BN-HistAN group more immature defences than the control group. In the RAN group no childhood predictors of adult defence style were found, whereas in bulimia nervosa, excessive parental control during childhood was a negative predictor of mature defences and physical abuse a positive predictor of immature defence style. These results provide some evidence that childhood adversity may constitute a vulnerability factor for the later development of bulimia nervosa, mediated by personality development.