Objectives Older people with kidney failure often have a limited range of treatment options, with few being well enough to receive a transplant. Instead, they either start dialysis or have ‘conservative kidney management’ (CKM). CKM involves care that focuses on managing the symptoms of kidney failure and maintaining quality of life in the absence of dialysis. The relative ability of dialysis and CKM to make older people live longer and feel better is uncertain. This study aimed to describe how older patients understand and decide between dialysis and CKM, as evidence suggests they may not be fully supported to make informed decisions between these treatments. Design Qualitative study using semistructured interviews, analysed using inductive thematic analysis and constant comparative techniques. Setting Three UK specialist kidney units. Participants Adults with estimated glomerular filtration rate (eGFR) <20 and aged over 80 years, irrespective of comorbidity or over 65 if living with two additional long-term conditions or frailty. Participants were purposively sampled to maximise clinicodemographic variation, and recruitment was continued until no new major themes were arising in the analysis. Results Eight men and seven women with a median age of 81 (range 65–90), and a median eGFR of 12 were interviewed. Three themes were identified: (1) ‘Do dialysis or die’, where not having dialysis was equated with death; (2) The ‘need’ for dialysis, where haemodialysis was perceived as the default treatment and (3) Weighing-up quality and quantity of life, relating to the trade-offs made between treatment benefits and burdens. Participants appeared unlikely to recognise the uncertain survival benefits of dialysis. Our study took place in England and all the participants were white British. As culture and faith can play a large part in decisions involving life and death, our findings may not be applicable to those in other communities. Participants were recruited from three centres, limiting the breadth of approaches to kidney failure management. Conclusions For older people who face short lives irrespective of treatment for kidney failure, unfamiliarity with treatment options, the desire to live and the ‘do or die’ notion conspire to cast haemodialysis as inevitable, regardless of whether this is the most appropriate treatment. To best enable shared decision-making, clinicians should present kidney failure treatment options in an accurate and balanced way, and respect and support older people who are deciding whether to have CKM or dialysis. This includes articulating uncertainty and supporting patients to make trade-offs in relation to what is important to them. Data are available on reasonable request. Participants consented to their anonymised data being made available to other researchers who want to analyse the data in the future. Data are managed by the University of Bristol and applications for their use should be made to the communicating author.