Sixty children and adolescents in end-stage renal failure who were undergoing either haemodialysis or continuous ambulatory peritoneal dialysis at one of five United Kingdom dialysis centres were assessed on psychosocial adjustment and adherence to their fluid intake, diet and medication regimes. Parental adjustment was also measured and data on sociodemographic and treatment history variables collected. A structured family interview and standardised questionnaire measures of anxiety, depression and behavioural disturbance were used. Multiple measures of treatment adherence were obtained, utilising children's and parents' self-reports, weight gain between dialysis, blood pressure, serum potassium level, blood urea level, dietitians' surveys and consultants' ratings. Correlational analyses showed that low treatment adherence was associated with poor adjustment to diagnosis and dialysis by children and parents (P < 0.01), self-ratings of anxiety and depression in children and parents (P < 0.001), age (adolescents tended to show poorer adherence than younger children, P < 0.001), duration of dialysis (P < 0.05), low family socioeconomic status (P < 0.05) and family structure (P < 0.01). These findings demonstrate the importance of psychosocial care in the treatment of this group of children. Future research should develop and evaluate psychosocial interventions aimed at improving treatment adherence.