Background: Intra-aortic balloon pump (IABP) is the simplest, most cost-effective, easy to implant, and explant in the coronary catheterization laboratory by an interventional cardiologist and can effectively be managed in an intensive care unit. Aim: To evaluate the effect of educational guidelines on nurses' performance regarding caring for patients with an intra-aortic balloon pump. Method: A quasi-experimental, pre and post-test intervention research design was implemented to conduct the current study. The study was conducted in the Cardio-Thoracic unit at Benha University. In addition, open-heart units at Nasser Institute Hospitals, Egypt. A convenience sample of all available nurses (64) (23 at Benha University & 41 at Nasser Institute Hospitals). Tools: Two tools were used to collect data: (I) A Pre-designed Questionnaire Sheet consisted of two parts (II) Nurses' Observational checklist for intra-aortic balloon pump care. Results: Showed the studied nurses' total knowledge about caring for patients with an intra-aortic balloon pump, 62.5% of nurses had an unsatisfactory level of total knowledge to be satisfactory during immediate and two months post guidelines implementation among 89.1% & 81.2%, respectively, while 67.2% of nurses had an incompetent level of total practice to be competent during immediate and two months post guidelines implementation among 92.2% & 79.7%, respectively and there was a highly statistically significant positive correlation between total knowledge and total practice at the post and follow up guidelines implementation. Conclusion: there was a statistically significant improvement in nursing performance regarding caring for patients with an intra-aortic balloon pump immediately after & 2 months post-guidelines implementation compared to pre-guidelines implementation. Recommendations: Improve the Practices of intensive care unit nurses through continuing educational sessions about intra-aortic balloon pumps to update their knowledge and practice.