A Primary Care Network (PCN) is a virtual network of general practitioners (GPs), sharing common resources and common clinical governance framework for effective chronic disease management. In this study, we analyzed the frequency of assessment as well as control of HbA1c, blood pressure (BP), and low-density lipoprotein (LDL) over time among adult patients with diabetes managed by a group of private GPs under PCN.Data, including clinical measurements of HbA1c, BP, and LDL from 2012 to 2015, of 943 subjects at 9 GP clinics that piloted PCN in Singapore in 2012 was obtained from the chronic disease register for this analysis.The total number of PCN patients increased from 371 in 2012 to 911 in 2015. The average HbA1c decreased from 7.5% in 2012 to 7.3% in 2015, with a significant yearly improving trend of -0.11% (P < .001). The trends in change for systolic BP and LDL were not statistically significant during the same follow-up period. Regular assessment of HbA1c decreased from 80% in 2012 to 55% in 2015. Such decreases were also found in BP and LDL assessments. We also found that receiving government subsidies under a national scheme was a major determinant for maintaining regular assessment, with patients so covered 3 to 20 times more likely to have regular assessments.The PCN model can help improve care and clinical outcomes in adult patients with diabetes in the private primary care sector. Investing greater financial and human resources to augment service capacity and expanding subsidy coverage may be important to ensure the effectiveness, scalability, and sustainability of such a model of care.