Background: Differences between the arms in systolic blood pressure (SBP) of ≥10 mmHg have been associated with an increased risk of mortality in patients with hypertensive and chronic renal disease. For the first time, we examined these relationships in a non-clinical population. Design: Cohort study. Methods: Participants were 4419 men (mean age 38.37 years) from the Vietnam Experience Study. Bilateral SBP and diastolic BP (DBP), serum lipids, fasting glucose, erythrocyte sedimentation rate, metabolic syndrome, and ankle brachial index were assessed in 1986. Results: Ten per cent of men had an interarm difference of ≥10 and 2.4% of ≥15 mmHg. A 15-year follow-up period gave rise to 246 deaths (64 from cardiovascular disease, CVD). Interarm differences of ≥10 mmHg were associated with an elevated risk of all-cause mortality (hazard ratio, HR, 1.49, 95% confidence interval, CI, 1.04–2.14) and CVD mortality (HR 1.93, 95% CI 1.01–3.69). After adjusting for SBP, DBP, lipids, fasting glucose, and erythrocyte sedimentation rate, associations between interarm differences of ≥10 mmHg and all-cause mortality (HR 1.35, 95% CI 0.94–1.95) and CVD mortality (1.62, 95% CI 0.84–3.14) were significantly attenuated. Conclusions: In this non-clinical cohort study, interarm differences in SBP were not associated with mortality after accounting for traditional CVD risk factors. Interarm differences might not be valuable as an additional risk factor for mortality in populations with a low risk of CVD.