Objective: Measuring the quality of primary care practice in Japan is difficult due to insufficient clinical data. To change the situation, the first nationwide primary care registry trial in Japan called J-DOME was launched for type 2 diabetes mellitus in 2018, and expanded to assess hypertension by 2020. In this cross-sectional analysis, we compare the patients with hypertension managed by hypertension specialists with those by non-specialists in the primary care settings. Design and Method: A total of 2,161 patients with hypertension were registered in 2021 (1,583 by non-specialists and 578 by specialists). Data were registered to the web-based registry system directly by the participating doctors or their staff. Clinic office blood pressure (BP) captured at the last visit (mandatory item), and the most recent self-measured home BP (not mandatory) were registered. The registered data were analyzed and compared between the two groups classified by whether the physicians were hypertension specialists or not. Results: Average age, body mass index (BMI), and duration of hypertension were 69.7 years, 25.3 kg/m2, and 12.8 years in the non-specialist group and 70.5 years, 25.2 kg/m2, and 13.2 years in the specialist group, respectively. The average systolic/diastolic office BP was 134.9/75.2 mmHg in the non-specialist group and 134.9/75.7 mmHg in the specialist group, and patients with systolic BP > = 140 mmHg consisted of 34.2% and 35.8%, respectively. The average home BP was 127.9/75.7 mmHg in the non-specialist group (n = 722, 45.6% of this group registered home BP) and 125.9/74.9 mmHg in the specialist group (n = 419, 72.5%). The HbA1c in the hypertension non-specialist group averaged 6.6% compared with 6.2% in the specialist group (p < 0.001). The ratio of prescribed antihypertensive medications was significantly different between the non-specialist and specialist groups (Figure). As for education on sodium intake, 80.7% of the patients with non-specialists received the education compared to 91.8% of those with specialists, and the average daily sodium consumption was 9.0 g (n = 426) and 8.7 g (n = 365), respectively. Conclusions: Although the office BP and essential characteristics were similar, the evident differences between the specialist and non-specialist groups were identified in hypertensive medications and education on sodium intake. Furthermore, the number of home BP data registered in the non-specialist group was limited, which urges further promotion of home BP measurement. The J-DOME study will continue to call for far more registration to provide the benchmark of practice quality in Japanese primary care settings.