Background, Psychological Capital is seen as a core concept in the positive organizational behavior (POB) Psychological capital is considered an important composite construct that can help in addressing human capital issues in organizations. According to, Psy Cap places emphasis on the positive nature and strengths of an employee and the role that he or she has in stimulating levels of grow. Nurses need to educated psychological capital to improve work engagement levels which has a significant impact on patients and organization’ outcomes. This study aims to assessing the effect of educational program regarding psychological capital on work engagement. Design: A quasi-experimental study design was used. Setting: The study was conducted at5 critical care units. In Ain Shams specialized hospital that affiliated to Ain Shams University hospitals? The sample included 129 nurses out of 190who working in above mentioned setting Tools for data collection three tools were used for data collection, namely: Psychological capital Knowledge questionnaire, psychological capital questionnaire, Work engagement questionnaire. Results: more than two third (53.5%) of studied nurses were in the age group <40 years. slightly more than three quarter (88.4%) of studied nurses were female and slightly more than half (51.9%) had diploma. Additionally, slightly more than third (39.6%) were years of experience <20 years. slightly less than half (49.6%) of nurse’s knowledge about psychological capital. It marked improvement of nurse knowledge of psychological capital (76.7%) in post program phase. While minimal decreasing was occurred (71.3%) in follow up phase of program but still more than the preprogram phase. more than three quarter of nurses had satisfactory level of psychological capital (77.5%) before the program. which improved to (81.4%) at the post program phase. And to slightly decrease throughout the follow up phase to reach (79.8%). there was improvement of levels regarding psychological capital about nurses in post and follow up program than preprogram... three quarter of nurses had satisfactory level of work engagement (75.9%) before the program. which improved to (82.9%) at the post program phase. There was statistically significant relation throughout program phases, with p-value (p<0.05). Conclusion: the study results concluded that the staff nurses in the study settings have generally low level of psychological capital knowledge, while their work engagement is slightly high. The training program is effective in improving their psychological capital and consequently increasing their work engagement. Finally, there was a positive effect of psychological capital tanning program on enhancing work engagement among staff nurses. Recommendations: Create positive psychological capital dynamic which plays an active role in boosting nurses’ levels of work engagement. It is obvious that nurses with high self-efficiency, hopeful, resistant to adverse conditions and optimistic will contribute more to the organization engagement.