Introduction Patients with non-muscle-invasive bladder cancer (NMIBC) have a good survival but are at high risk for tumour recurrence and disease progression. It is important to identify lifestyle habits that may reduce the risk of recurrence and progression and improve health-related quality of life (HRQOL). This paper describes the rationale and design of the UroLife study. The main aim of this study is to evaluate whether lifestyle habits are related to prognosis and HRQOL in patients with NMIBC. Methods and analysis The UroLife study is a multicentre prospective cohort study among more than 1100 newly diagnosed patients with NMIBC recruited from 22 hospitals in the Netherlands. At 6 weeks and 3, 15 and 51 months after diagnosis, participants fill out a general questionnaire, and questionnaires about their lifestyle habits and HRQOL. At 3, 15 and 51 months after diagnosis, information about fluid intake and micturition is collected with a 4-day diary. At 3 and 15 months after diagnosis, patients donate blood samples for DNA extraction and (dietary) biomarker analysis. Tumour samples are collected from all patients with T1 disease to assess molecular subtypes. Information about disease characteristics and therapy for the primary tumour and subsequent recurrences is collected from the medical records by the Netherlands Cancer Registry. Statistical analyses will be adjusted for age, gender, tumour characteristics and other known confounders. Ethics and dissemination The study protocol has been approved by the Committee for Human Research region Arnhem-Nijmegen (CMO 2013-494). Patients who agree to participate in the study provide written informed consent. The findings from our study will be disseminated through peer-reviewed scientific journals and presentations at (inter)national scientific meetings. Patients will be informed about the progress and results of this study through biannual newsletters and through the website of the study and of the bladder cancer patient association.