Cystic fibrosis and asthma have many psychosocial implications for patients and their relatives. These can stem from parental adaptational problems following diagnosis, negative illness perceptions, feeling 'different' and other associated developmental intrusions. In asthma, psychological factors arising from a variety of sources are known to 'trigger' attacks. For adolescents, psychological problems are hallmarked by loss (e.g. of identity, independence and peers) which results in re-appraisals of self-worth, depression and anxiety. Early intervention strategies and screening are crucial in ameliorating unsuccessful emotional adaptation and preventing chronic psychological morbidity. Behavioural and cognitive-behavioural interventions are particularly effective for both treatment-related behavioural problems (e.g. procedural distress, and poor feeding behaviour) and some psychological disorders (e.g. anxiety and depression). However, outcome depends on patients' motivation to change and willingness to collaborate. Where this is absent, less directive, but nonetheless effective, psychotherapies are utilised. Family therapy is also considered useful in addressing family dysfunction when thought to be intrinsic to the emotional problems.