OBJECTIVE: Previous studies have shown anti-cancer and anti-inflammatory benefits of glucosamine. This study was performed to prospectively evaluate the association between glucosamine supplementation and the mortality of multiple cancers based on the UK Biobank cohort study. MATERIALS AND METHODS: A total of 453,645 participants aged 38-73 who had no cancer at baseline were recruited between 2006 and 2010 and followed until March 2021. We used cox and poission proportional hazards models to explore the association between habitual use of glucosamine and cancer mortality. Subgroup analyses were conducted to understand the potential effect modifications of demographics, lifestyle factors, and health outcomes. Sensitivity analyses were performed to determine the robustness of the results. RESULTS: Of the participants, 88,224 (19.4%) reported habitual glucosamine use at baseline. There were 9,366 cancer deaths during a median follow-up of 12.1 years, and we observed a significant association between the use of glucosamine and lower overall cancer mortality (HR = 0.95, 95% CI = 0.90-1.00, < 0.05), kidney cancer (IRR = 0.68, 95% CI = 0.49-0.95, < 0.05), lung cancer mortality (IRR = 0.84, 95% CI = 0.74-0.95, < 0.05), and rectum cancer (IRR = 0.76, 95% CI = 0.59-0.98, < 0.05). Subgroup analysis showed that habitual glucosamine supplementation was correlated with lower overall cancer mortality among participants who were aged ≥ 60 years, male, current smoker, without high cholesterol and not obese. Sensitivity analysis showed that the results were stable. CONCLUSION: Habitual glucosamine use was significantly related to decreased overall cancer, kidney cancer, lung cancer, and rectum cancer mortality, based on data from the large-scale, nationwide, prospective UK Biobank cohort study.