Objectives.Patients' beliefs regarding illness and treatment are important to understand responses to chronic disease. The present study aimed (i) to assess the illness representations and treatment disruption beliefs of patients with end stage renal disease (ESRD), (ii) to determine whether beliefs about illness and treatment differ between different renal replacement therapies, and (iii) to examine whether these beliefs are associated with health related quality of life (HQoL).Method.A cross‐sectional sample of 262 ESRD patients, 145 dialysis and 117 kidney transplant recipients completed the illness perceptions questionnaire, the illness effects questionnaire, the treatment effects questionnaire and the short form 36 health survey. Measures of ESRD severity/co‐morbidity and biochemistry were also collected.Results.HQoL levels were higher in transplant patients. Dialysis patients reported more symptoms associated with ESRD (p<.001), stronger chronic timeline beliefs (p<.001), lower control beliefs (p<.05), and more illness and treatment disruptiveness (ps<.01). Illness and treatment disruptiveness, consequences and identity were inversely associated with HQoL whereas control was positively associated with HQoL. Multiple regressions indicated that treatment and illness disruptiveness, identity and consequences beliefs accounted for 22.9–67.6% of the variance HQoL although specific multivariate correlates differed across physical and emotional HQoL and between dialysis and transplantation.Conclusions.The beliefs that patients hold about their illness and treatment appear to be related to the type renal replacement therapy being undertaken. These cognitions have associations with HQoL in dialysis and transplantation that are independent of those of socio‐demographic and clinical