Despite increasing trends in the prevalence of overweight and obesity, fatness phobia is common during female adolescence. This study has demonstrated a high level of dissatisfaction with body weight in a sample of Dublin schoolgirls aged 15 y. Of 420 subjects, 59% reported that they wanted to be slimmer and 68% had previously tried to lose weight. Contrary to expectations, overweight girls were not found to hold the monopoly on such dissatisfactions. Normal weight and even underweight girls also expressed a desire to be thinner and reported using unhealthy weight control practices including random avoidance of staple foods, fasting, smoking and purging, in their pursuit of the 'perfect' female figure. Obesity prevention programmes which target adolescent girls 'at risk' of overweight and obesity, must take cognizance of their profound fear of fatness, otherwise the use of harmful slimming strategies may be further increased as teenage girls frantically try to lose weight and to avoid the stigma associated with female fatness.