Mushroom is rich in protein, fiber, vitamins, and essential amino acids. A relationship between mushroom consumption and a lower all-cause mortality risk has been reported. This study aimed to examine the association of mushroom consumption with all-cause and cause-specific mortality. Data were extracted from the Korean Genome and Epidemiology Study cohort. Mortality outcomes were confirmed from 2001-2020 death records provided by the Korea National Statistical Office. Mushroom intake was assessed using food frequency questionnaires and categorized into four groups: none, <1 serving per week, 1-3 servings per week, and ≥3 servings per week. Cox proportional hazard regression was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality. The 152 828 participants ≥40 years had a mean age of 53.7 years. Over a mean 11.6-year follow-up, 7085 deaths were recorded. In men, consuming <1 and 1-3 servings per week of mushroom was associated with lower risks of all-cause (HR = 0.858, 95% CI = 0.793-0.929; HR = 0.902, 95% CI = 0.819-0.993) and cardiovascular disease (CVD) (HR = 0.767, 95% CI = 0.632-0.930; HR = 0.762, 95% CI = 0.601-0.967) mortality than non-consumption. In women, consuming <1 and 1-3 servings per week of mushrooms was associated with a lower risk of all-cause mortality (HR = 0.864, 95% CI = 0.784-0.952; HR = 0.869, 95% CI = 0.771-0.980) than non-consumption. This prospective cohort study demonstrated that low and medium mushroom consumption is associated with a lower risk of all-cause mortality in men and women. However, only men who consumed <1 and 1-3 servings per week of mushrooms exhibited a lower risk of CVD mortality.