OBJECTIVES: To evaluate the correlation between serum glycosylated hemoglobin (HbA1c) levels and the risk of prostate cancer incidence and mortality, providing a comprehensive analysis to inform preventative and clinical strategies. METHODS: A systematic review and meta-analysis was conducted including studies based on their documentation of prostate cancer incidence and mortality related to HbA1c levels, with a minimum of 3 risk-related data levels. The Newcastle-Ottawa Quality Assessment Scale (NOQAS) was used for quality assessment and risk of bias evaluation. We employed generalized least squares (GLS) to assess the linear trend within individual studies and combined these estimates using a random effects model. Additionally, we utilized a restricted cubic spline (RCS) model to investigate potential nonlinear trends. RESULTS: A total of 13 studies were included in the quantitative synthesis ultimately. The quantitative analysis did not find a significant association between HbA1c levels and prostate cancer incidence. However, a significant positive correlation was revealed between HbA1c levels and both cancer-specific mortality (CSM) and all-cause mortality (ACM), with a 1% increase in HbA1c levels associated with a 26% increase in CSM and a 21% increase in ACM. CONCLUSION: The HbA1c level is significantly associated with increased prostate cancer mortality. The results highlight the importance of considering blood sugar control in the comprehensive risk assessment for prostate cancer, particularly among the nondiabetic population.