Cystic Fibrosis (CF) is an intriguing disease that raises myriad issues relating to health, wellness, treatment and adjustment for families living with the disease, as well as for healthcare and human-services professionals working with these families. To begin to understand this complex illness, we must explore the biological, physical and psychosocial needs and strengths of families living with cystic fibrosis. In addition, we need to look at how living with CF can affect child and family development and the adjustment into adolescence and beyond. This paper begins with an introduction to the Family-Systems- Illness Model, an adjustment model that provides a clear framework for social workers and other health care professionals working with clients with CF. The paper then looks at cystic fibrosis, its etiology, symptoms, course and prognosis. It then discusses how the particular features of CF can affect family and child/adolescent development. The paper continues with a discussion of the Family-Systems-Illness Model, and it ends with some questions that are important for a social worker to include when assessing a family caring for a child with cystic fibrosis.