Background and Objectives: Diabetes is one of the most common diseases dealt with by physicians in primary healthcare centers (PHCs). The disease is associated with macrovascular and microvascular complications, especially in those with long disease duration and uncontrolled diabetic nephropathy, which is one of the most common microvascular complications among diabetic patients. This investigation assessed the practices of physicians working at PHCs in terms of diabetic nephropathy screening, management, and referral. Materials and Methods: This study is a cross-sectional investigation targeting physicians working at PHCs in the Jazan region of Saudi Arabia between March and August of 2023. Data were collected via a self-administered questionnaire, which was distributed via online platforms. The questionnaire included sections measuring physicians’ demographic data and associated factors regarding training, the availability of resources, and practices in diabetic nephropathy, including screening, management, and referral. Chi-squared tests were used to assess associations between the practices of physicians and the measured demographics. Result: A total of 234 physicians participated in the investigation. The median age of the participants was 35 years. The adherence level of practice toward diabetic nephropathy according to American Diabetes Association (ADA) guidelines ranged from 40 points (the highest adherence level of participants) to 19 points (the lowest adherence level of participants), with a median of 33 points. Higher adherence levels were noted among physicians in Saudi Arabia, physicians with higher education levels, physicians specializing as family physicians or diabetologists, physicians who reported attending online and on-site training at diabetic centers, physicians who reported continuous access to urine and serum creatinine tests, and physicians who reported continuous access to the American Diabetes Association guidelines (p < 0.05). Conclusions: There are several factors associated with the level of adherence in diabetic nephropathy practice, such as physicians’ education level, specialty, training, and access to guidelines. The findings suggest the need for more training for PHC physicians in the care of patients affected by or at risk of diabetic nephropathy.