Background: Adherence with the prescribed medical regimen is a crucial factor for achieving good therapeutic results in dialysis patients. This study aimed to: Assess adherence of chronic renal failure patients undergoing maintenance hemodialysis with therapeutic regimen. Subjects and Method: Setting:  In the dialysis Unit at International Educational Hospital, Student Educational Hospital of Tanta University and Health Insurance Hospital. Subjects: A convenience sample of 200 adult patients with CRF admitted to Hemodialysis Units at Scheduled. Three tools were used, Tool (I) Structured interview schedule.Tool (II)  Patient's knowledge assessment questionnaire, Tool (III) GR-Simplified Medication Adherence Questionnaire Hemodialysis. Results : It was observed that vast majority (83%) of studied patients had adherence with medication , more than two third (68.5%) of studied patients had adherence with follow up , while more than half (55.5%) had  in-adherence with dietary instructions and (44.5%) had adherence .there was a high positive significant correlation between knowledge score and adherence . Conclusion:  the results revealed that studied patients with good knowledge score appeared adherence with the GR-SMAQ-HD scale, while studied patients who had poor knowledge appeared In-adherence. Recommendations: Counseling should be provided for all patients who are undergoing Hemodialysis that helps in preparation of them and give advice in adherence of therapeutic regimen   .