To evaluate the relationship between hypertension and knee discomfort severity in knee osteoarthritis (OA) patients. Cross-sectional analysis of OAI baseline data. Participants with knee OA (N=1,363) were divided into four groups based on blood pressure: systolic less than 120 mm Hg and diastolic less than 80 mm Hg; 120 ≤ systolic < 130 mm Hg and 80 ≤ diastolic < 90 mm Hg. In the previous 7 days, pain severity was estimated with the Western Ontario and McMaster Universities Osteoarthritis Index Pain Subscale in the past 48 hours, Knee Injury and Osteoarthritis Outcome Score (KOOS) Pain Subscale in the past 48 hours, and numeric rating scale (NRS) in the past 30 days. Hypertension was evaluated for its association with knee pain severity using linear regression. Compared with the normal BP group, individuals with stage 2 hypertension reported significantly higher OA knee pain severity by KOOS in the past 7 days (β=-2.05 [95% CI-4.09, -0.01], P=0.049) and by NRS in the past 30 days (β=0.31 [95% CI 0.01, 0.62], P=0.045) after adjustments for demographic and medical factors. Hypertension was linked with a greater knee OA pain severity in persons with knee OA.