BACKGROUND: The COVID-19 pandemic has disrupted regular health care with potential consequences for non-COVID diseases like cancer. To ensure continuity of oncological care, guidelines were temporarily adapted. OBJECTIVE: To evaluate the impact of the COVID-19 outbreak on bladder cancer care in the Netherlands. METHODS: The number of bladder cancer (BC) diagnoses per month during 2020-2021 was compared to 2018-2019 based on preliminary data from the Netherlands Cancer Registry (NCR). Additionally, detailed data were retrieved from the NCR for the cohort diagnosed between March 1st-May 31st 2020 (first COVID wave) and 2018-2019 (reference cohort). BC diagnoses, changes in age and stage at diagnosis, and time to first-line treatment were compared between both periods. Changes in treatment were evaluated using logistic regression. RESULTS: During the first COVID wave (week 9–22), the number of BC diagnoses decreased by 14%, corresponding with approximately 300 diagnoses, but increased again in the second half of 2020. The decline was most pronounced from week 13 onwards in patients≥70 years and patients with non-muscle invasive BC. Patients with muscle-invasive disease were less likely to undergo a radical cystectomy (RC) in week 17–22 (OR = 0.62, 95% CI = 0.40–0.97). Shortly after the start of the outbreak, use of neoadjuvant chemotherapy decreased from 34% to 25% but this (non-significant) effect disappeared at the end of April. During the first wave, 5% more RCs were performed compared to previous years. Time from diagnosis to RC became 6 days shorter. Overall, a 7% reduction in RCs was observed in 2020. CONCLUSIONS: The number of BC diagnoses decreased steeply by 14% during the first COVID wave but increased again to pre-COVID levels by the end of 2020 (i.e. 600 diagnoses/month). Treatment-related changes remained limited and followed the adapted guidelines. Surgical volume was not compromised during the first wave. Altogether, the impact of the first COVID-19 outbreak on bladder cancer care in the Netherlands ...