Aims: Was to evaluate the effect of applying nursing guidelines on patients' awareness about HBOT. Research design: auasi experimental design has been used to carry out this study on a sample of 200 adult diabetic patients both sex since two years ago within 6 months. Study was conducted at internal medicine department and diabetic outpatient clinic at Assiut University Hospitals. Tools: Three tools used; A structured interview questionnaire sheet, Designed Nursing guidelines and Patient evaluation sheet. Results: Out of 200 patients, the highest percent of studied sample were male (53.3%), their age 50- 65 years (39.5%) married and living in rural area (80.5), read and write (59.0%), not working (59.0%) , (84.0%) had family history from other relatives, and (33.0%) of patients were having hypertension with diabetes mellitus and the majority (ninety five percent and(hundred percent) had poor level of knowledge about diabetic foot and HBOT during pre-test followed by (hundred percent), (ninety percent) had good knowledge level about diabetic foot and HBOT after implementation nursing guidelines. Conclusion: Diabetic foot patients exposed to several complications, improving patient's awareness about HBOT can favorable affect the incidence of these complications. Recommendation: Organize regular counseling sessions for meeting the patients' information about diabetic foot and HBOT.