This study compares the characteristics of women with anorexia nervosa with those of women who have all the diagnostic features of that disorder except amenorrhoea. The study uses data from a large community epidemiological survey of the mental health status of household residents in Ontario, Canada. A multi-stage stratified sampling design generated a sample of 4285 females aged 15-64. DSM-III-R diagnoses were made using the Composite International Diagnostic interview. Eighty-four out of 4285 female respondents met full or partial-syndrome criteria for anorexia nervosa. Comparison of these two groups revealed few statistically significant differences in terms of demographics, psychiatric comorbidity, family history or early experiences. Amenorrhoea did not discriminate between women with anorexia nervosa and women with all the features except amenorrhoea across a number of relevant variables. The authors question the utility of amenorrhoea as a diagnostic criterion.