Background: Primary Percutaneous coronary intervention is a non-surgical, invasive procedure used to treat blockage or narrowing of the coronary artery and improve blood supply to the ischemic tissue. Aim: to investigate the effect of nursing discharge instructions on outcomes for patients undergoing primary percutaneous coronary intervention. Subjects and Methods: Research design: A quasi-experimental design. Sample: 200 adult patients who were admitted for percutaneous coronary intervention. Patients divided equally into two groups study and control (100 for each). Setting: the cardiac catheterization unit and Cardiovascular Medicine Department at Assiut University Heart Hospital. Tools: Patients assessment sheet, readmission risk assessment, complications assessment sheet, and re-admission rate assessment sheet. Results: a statistically significant difference between study and control group post application of nursing discharge instructions regarding knowledge, and complications was (<0.001**). LACE index was moderate for both study and control group. The main cause of re-admission for both study and control group was myocardial infarction (50%, and 46.2( respectively. Conclusion: Nursing discharge instructions significantly improve patients' knowledge and reduce complications and readmission rate among patients undergoing percutaneous coronary intervention. Recommendation: Nursing discharge instructions (brochure) should be used in hospitals for patients with primary percutaneous coronary intervention.