Treatment aimed at achieving an ideal nutritional status is an integral part of the management of patients with cystic fibrosis (CF). Emphasis is continually placed upon dietary intake and weight. The effects of this on eating behavior and self-perceptions are unclear. This work compared male and female CF adults with a healthy male and female control population with regard to (a) clinical variables, (b) actual, perceived, and desired body shape/body mass index (BMI), and (c) body satisfaction, eating behaviors and attitudes, and self-esteem. Clinical data were recorded for 221 adults with CF and 148 healthy controls. All subjects completed BMI Charts (perception of body weight/BMI), the Eating Attitudes Test, and scales of body satisfaction and self-esteem. CF patients had poorer lung function and nutritional status than controls. Control males accurately perceived their body shape/BMI and were content with it, whereas CF males viewed their BMI as greater than it actually was and desired to be much heavier. Control females viewed their body shape/BMI as less than it actually was and desired to be even slimmer, in comparison with CF females, who perceived their BMI as less than it actually was but were happy with their perceived shape/weight. Control subjects, especially females, dieted to a greater extent and were more preoccupied with food (with binge eating and intended vomiting) than CF patients. Conversely, those with CF reported greater pressure from others to eat than did controls. More problems with food/eating behavior were associated with less body satisfaction and reduced self-esteem. In comparison with a healthy control population, the perceptions and behaviors of CF adults relating to eating, weight, and body image are not abnormal. Indeed, females with CF have fewer problems than their healthy peers.