Twenty-seven adolescents and young adults with cystic fibrosis were studied to evaluate the phychological impact of this chronic illness. At first glance, most patients appeared to function adequately on a daily basis. However, four sources of psychological stress, leading to emotional disturbance, were identified: altered physical appearance causing distorted body images and denial of sexuality, strained interpersonal relationships resulting in isolation and mental strain, conflicts in upbringing, and increased awareness of the future and of death. Guidelines for the physician treating these young adults and their families include: (1) encouragement for greater involvement by the patient's father; (2) assisting the mother to find outside interests and to allow more independence to the patient; (3) stressing communication about cystic fibrosis within the home; (4) emphasizing outside activity for each patient; (5) repeated discussions of the patient's concerns while emphasizing his strengths; (6) anticipation of problems, specific to cystic fibrosis, such as sterility in males; and (7) encouragement of interpatient communication.