Background: Papworth breathing is a relaxation technique through which patients can change physical, emotional, and stressful behaviors using their thought. This technique is based on muscle relaxation and the patient learning how to achieve mental relaxation. Biological, social, and psychological aspects of children are all impacted by diabetes, a chronic illness. Stress and pressure from parents, doctors, and other carers are a part of everyday life for kids with diabetes mellitus. Aim: The study aimed to evaluate the effect of evidence-based papworth breathing technique on anxiety among school-age diabetic children. Subjects and Method: A quasi-experimental (pre-posttest) design implemented for 100 diabetic child (50 study group and 50 control group). Two tools included: Tool I: A designed direct interview form established by the investigators that included personal and clinical data of children. Tool II: Screen for Child Anxiety Related Disorders (SCARED). It was adopted from Birmaher et al. (1997). Results: The mean of all symptoms of anxiety disorders in the study group is less than that of a control group in the post-program phase and follow-up phase with P. Value <0.01. Conclusion: Papworth technique led to an effective improvement in the management of anxiety in daily life. Recommendations: Hospitals should include Papworth technique in their policies and care plans as basic intervention care for children with chronic illness.