Caloric intakes of preadolescent and adolescent girls and boys with cystic fibrosis (CF) were compared in order to evaluate the possibility that poor caloric intake contributes to poor nutritional status and high mortality among girls with CF. Fifty-six CF patients (26 girls and 30 boys), 10-15 years old, completed a 3-day food record, answered a short questionnaire, and underwent anthropometric and pulmonary function assessment. The mean ages of the girls and boys were similar, but the height and weight percentiles of the girls were lower than those of the boys (p = 0.02). Mean caloric intakes were no different (116% and 112% of the recommended nutrient intake in the girls and boys, respectively). Nutritional status, as determined by weight as a percentage of ideal weight for height, mean triceps skinfold thickness, and midarm muscle circumference, was normal and similar in both sexes. Most girls and boys with CF in this study had an appropriate perception of their body weight. Pulmonary function tests suggested mild lung disease with no significant difference between girls and boys (forced expiratory volume in 1 s of 82.2% and 79.8% of predicted values, respectively). The similar nutritional and pulmonary status of the girls and boys with CF in this age group is in contrast to previous reports. This finding may be the result of our policy, introduced > 15 years ago, of expecting normal growth, by paying close attention to enzyme therapy and encouraging high energy intake from the time of diagnosis. It remains to be seen whether boys and girls continue to maintain similar nutritional and pulmonary status at a later age and whether both sexes experience a similar mortality rate as they age.