Purpose The Renal cell cancer: Lifestyle, prognosis and quality of life (ReLife) study is set up to obtain insight into the association of patient and tumour characteristics, lifestyle habits and circulating biomarkers with body composition features in patients with localised renal cell cancer (RCC). Further, it aims to assess the association of body composition features, lifestyle habits and circulating biomarkers with clinical outcomes, including health-related quality of life. Participants The ReLife study is a multicentre prospective cohort study involving 368 patients with newly diagnosed stages I–III RCC recruited from January 2018 to June 2021 from 18 hospitals in the Netherlands. At 3 months, 1 year and 2 years after treatment, participants fill out a general questionnaire and questionnaires about their lifestyle habits (eg, diet, physical activity, smoking and alcohol consumption), medical history and health-related quality of life. At all three time points, patients wear an accelerometer and have blood samples taken. CT scans for body composition analysis are being collected. Permission is asked for collection of tumour samples. Information about disease characteristics, treatment of the primary tumour and clinical outcomes is being collected from medical records by the Netherlands Cancer Registry. Findings to date A total of 836 invited patients were eligible and 368 patients were willing to participate and were included (response rate 44%). The mean age of patients was 62.5±9.0 years and 70% was male. The majority had stage I (65%) disease and were treated with radical nephrectomy (57%). Data collection at 3 months and 1 years after treatment have been finalised. Future plans Data collection at 2 years after treatment is expected to be finalised in June 2023 and longitudinal clinical data will continue to be collected. Results of studies based on this cohort are important to develop personalised evidence-based lifestyle advice for patients with localised RCC to enable them to get more control over ...