Background: In clinical practice, mentoring is a continuum of education required for leadership, development, and training of competent health care providers, as it offers a means of enhancing workforce performance and engagement of nurses. Aim of the study: To investigate the effect of mentoring educational program for head nurses on nurses' work engagement. Study design: A quasi-experimental design was utilized. Setting: The study was conducted at inpatient units of medical, surgical departments at Benha University Hospital. Study Subject: All available (60) head nurses during data collection period and a simple random sample of 200 nurses. Tools of data collection: Four tools were used; Tool (1) Mentoring knowledge assessment questionnaire, Tool (2) Mentoring skills observational checklist, Tool (3) Head nurses' Attitude toward mentoring questionnaire and Tool (4) Work engagement scale. Results: Nearly three quarters of head nurses (73.3%) had inadequate knowledge regarding mentoring at preprogram phase, which improved to be 98.3% and 86.7 % had adequate knowledge at immediate post and follow up phases, respectively. More than three quarters (78.5%) of nurses had low work engagement level at preprogram phase, and improved to 70.5% at immediate post and become moderate level (58.5%)at  follow up phases  had high work engagement. Conclusion: There was a positive statistically significant correlation between head nurses' total knowledge skills and attitude regarding mentoring and nurses' work engagement at immediate post program was found. Recommendation: Initiating in-service education and training programs in all departments for refreshing and increasing head nurses' knowledge and skills especially about mentoring which in turn increase nurses' engagement.