Background: Delegation is an art and skill of professional nursing that is considered as one of the core concepts and major element of the organizing and directing functions of head nurses and managing their time. Using effective delegation by head nurse can motivate the subordinates' leaders to do more than what is being expected. Aim: The aim of the study was to determine theefficacy of guidance program on head nurses practice for delegating managerial tasks in Intensive care units. Subjects and Method: Setting: Study was conducted at ICUsof Tanta Main University Hospital including Cardiac, Medical, Neurology and Chest ICUs, Emergency Hospital including Anesthesia and Medical ICUs, and Tanta International Teaching Hospital including Cardiac, Medical and Chest, Burn and Anesthesia ICUs. Subjects: All (24) head nurses and (54) subordinate leaders working in ICUs are participated in the study. Tool: Three tools were used; (1) Delegation of managerial tasks knowledge questionnaire (2) Head nurses practice for delegation of managerial tasks. (3) Barriers of subordinate leader's acceptance of delegated managerial tasks. Results: Preprogram 66.7% of head nurses had poor knowledge and79.2% had unsatisfactory total practice level for delegation of managerial tasks. Changed post program to be majority(79.2%) had good knowledge and 83.3%had satisfactory total practice level for delegation of managerial tasks. Majority (72.2%) of subordinate leader had high and moderate levels of barriers for acceptance of delegated managerial tasks. There was statistical significant positive correlation between head nurse's total knowledge and practices about stepsof delegationmanagerial tasks preprogram at (p =0.572) and post program at (p =0.640). Conclusion: The designed and implemented guiding program significantly improve head nurses' knowledge and practice about delegation of managerial task. Recommendations: Periodical orientation program about importance and steps of delegation process of managerial task is recommended to be implemented regularly.