Background Diabetes is a rapidly growing health problem worldwide. In 2019, the International Diabetes Federation (IDF) estimates that Egypt is the 9th country worldwide with about 8,850,400 cases and a prevalence of 15.2% in adults. By 2045, Egypt is expected to be the 7th country worldwide. Several factors affecting glycemic control are related to patients, physicians, and the infrastructure of primary health care facilities (PHCFs). The effect of health care infrastructure and resources is not well studied. This cross-sectional study aims to explore factors affecting glycemic control among subjects with diabetes visiting PHCFs in the Mansoura District. A questionnaire was done to assess these factors among subjects with diabetes, primary care physicians (PCPs), and PHCFs infrastructure and resources. Three hundred and two subjects with diabetes attending PHCFs in the Mansoura District underwent a detailed clinical history. Also, HbA1c was obtained. Results Factors in patients that affect diabetic control include patient’s education and occupation and their smoking status. Practicing physical exercise is important for diabetes control. Physicians can affect diabetes control by their rural residence, older age, participation in diabetes training, early graduation year, longer durations since started dealing with subjects with diabetes, and following guidelines. Resources of infrastructure have a role in diabetes control. Metformin and investigation availability has a positive association with diabetes control. Conclusion Patients, physicians, and resources of infrastructure have a role in diabetes control.