Aim: This study aimed to: (1) to investigate PHC nurses’ level of diabetes-related nutrition knowledge; (2) to assess PHC nurses’ perception about knowledgeability and role in provision of diabetes nutrition education; (3) to explore the relationship between nurses’ diabetes-related nutrition knowledge with nurses’ background and organizational support.Background: Diabetes is a prevalent global health issue that can be diagnosed and managed in primary health care (PHC). Nurses are the largest number of health care providers who work with diabetic patients to manage its complications. One of significant diabetes management components is nutrition. Method: A descriptive cross-sectional, correlational study with 163 PHC nurses in Jazan, Saudi Arabia was conducted. Self-administered survey was used with each nurse two times for test-retest reliability. Data was analyzed using descriptive statistics and correlational test. Results: Nurses had limited diabetes-related nutrition knowledge with a mean score of 11.65 out of 20, yet the majority perceived themselves competent and responsible in provision nutrition education to diabetic patients. The availability of time to attend courses and read about diabetes nutrition, and being informed about time and venue programmers of diabetes diet were positively correlated with nurses’ diabetes-related nutrition knowledge.Conclusion: The study highlighted the need to improve the education of PHC nurses in the field of diabetes nutrition, in particular the majority of PHC nurses regarded themselves as responsible for the nutrition education of diabetic patients. As well, organizational factors, such as availability of time and support, should be considered to enhance nurses’ knowledge.