Objective The Toranomon Hospital Health Management Center Study 16 (TOPICS 16) showed that higher fasting plasma glucose (FPG) indicated increased risk of hypertension, but glycosylated hemoglobin A1c (HbA1c) did not. This study aimed to investigate whether HbA1c was associated with the risk of hypertension. Methods A prospective study was carried out on 4 586 men initially free of hypertension, diabetes, and cardiovascular disease who taking regular physical examination in our hospital to assess the relationship of baseline HbA1c with hypertension. Their baseline clinical data were collected. The quintiles and clinical cutpoints of HbA1c for the risk of hypertension were considered and analyzed. Results During a median follow-up of 11.5 years, 2 027 of the cohort (44.2%) developed hypertension. In the model adjusted for traditional cardiovascular risk factors, the hazard ratios (HR) from the lowest (＜4.75%) to the highest (≥5.18%) quintile of HbA1c were 1.0 (referent), 0.99 (0.93, 1.07), 1.06 (0.99, 1.14), 1.08 (1.02, 1.15), and 1.22 (1.17, 1.35). When using clinical cutpoints of FPG (＜4.7, 4.8?5.2, 5.3?5.7, ≥5.7mmol/L), the model adjusted for traditional cardiovascular risk factors showed that the HR from the lowest (＜4.7mmol/L) to the highest (≥5.7mmol/L) level of FPG were 1.0 (referent), 0.95 (0.92, 1.05), 0.96 (0.91, 1.06), and 1.01 (0.95, 1.10) respectively. Conclusion HbA1c in men without diabetes is associated with risk of hypertension.