Back ground: Diabetes is one of the most common and fastest growing diseases worldwide. Diabetic foot ulcers (DFUs) are a prevalent complication of diabetes mellitus and account for significant morbidity and mortality. Hyperbaric Oxygen Therapy (HBOT) is one of the advanced therapeutic modalities for wound management. Aim: the study aimed to assess factors affecting compliance of patients with diabetic foot ulcer undergoing hyper baric oxygen therapy. Design: descriptive exploratory design was utilized for conduct the current study. Setting: this study was carried out at hyper baric oxygen therapy at Nasser institute for research and treatment. Study subjects: A Purposive sample of 30 Patients with diabetic foot ulcer on hyper baric oxygen therapy. Tools: 1) patient interviewing questionnaire. 2) patient related factors questionnaire.3) Compliance assessment tools. Results: the patient had 50% satisfactory knowledge about diabetes, 93.3% of them the cost of treatment affect the family expenses, 56, 7% of them had severe social dysfunction, 43.3% of the studied patient had severe anxiety, 36. % of them had compliance toward therapy Conclusion: half of studied patients had satisfactory knowledge, highly significant positive correlation among total knowledge & total compliance. Highly significant negative correlation among total social & total compliance, statistically significant relation between total compliance and total social factor, monthly. Statistically significant relations between total compliance anxiety, environment factor and total knowledge, Recommendation: education program for diabetic foot ulcer, hyper baric oxygen therapy to the patient.