Implantable Port-A- Catheter is a central vascular access device that provides direct access to large blood vessels. The device has become an integral part of daily oncology nursing clinical care, improving nurses' knowledge and practice is crucial for compliance minimizing complications, and improving patient outcomes. Aim:  It was to evaluate the effect of evidence-based guidelines regarding port-a-Cath care on oncology nurses' performance and patients' health outcomes. Design: A quasi-experimental design was used. Setting: medical oncology and nuclear medicine unit and inpatient unit at Benha University Hospital, Egypt. Sample: A convenient sample of (67) Oncology nurses and a purposive sample of 134 patients who connected to port-a-cath., they were classified into two groups; group A was assessed pre-evidence-based nursing guidelines intervention; and group B was evaluated post-evidence-based nursing guidelines intervention. Both groups of patients had been cared for by the same group of studied nurses, concerning the port-a-catheter procedure. Tools for data collection: A structured Questionnaire, nurse's practice observational Checklist, Patient assessment, and clinical health outcomes data assessment. Results: There were statistically significant differences between pre & post-EBNGI regarding the knowledge and practice of the studied nurses regarding care for the patient with port-A-catheter. Patients ( Group B) who had been cared for by the same group of studied nurses post-EBNGI had l fewer complications as compared with patients (Group A) who had been cared for by the same group of studied nurses pre-EBNGI, but this decrease was not statistically significant difference in relation to their health outcomes . Conclusions: The evidence-based nursing guidelines intervention were helpful in the improvement of the nurses' knowledge and practices for the prevention of port-A-catheter-related complications among oncology patients. Recommendations: Periodic educational programs regarding port-a-catheter care for nurses who provide care for patients connected to port-a-cath. Implantable Port-A- Catheter is a central vascular access device that provides direct access to large blood vessels. The device has become an integral part of daily oncology nursing clinical care, improving nurses' knowledge and practice is crucial for compliance minimizing complications, and improving patient outcomes. Aim: It was to evaluate the effect of evidence-based guidelines regarding port-a-Cath care on oncology nurses' performance and patients' health outcomes. Design: A quasi-experimental design was used. Setting: medical oncology and nuclear medicine unit and inpatient unit at Benha University Hospital, Egypt. Sample: A convenient sample of (67) Oncology nurses and a purposive sample of 134 patients who connected to port-a-cath., they were classified into two groups; group A was assessed pre-evidence-based nursing guidelines intervention; and group B was evaluated post-evidence-based nursing guidelines intervention. Both groups of patients had been cared for by the same group of studied nurses, concerning the port-a-catheter procedure. Tools for data collection: A structured Interview Questionnaire, nurse's practice observational Checklist, Patient assessment, and clinical health outcomes data assessment. Results: There were statistically significant differences between pre & post-EBNGI regarding the knowledge and practice of the studied nurses regarding care for the patient with port-A-catheter. Patients. Conclusions: The evidence-based nursing guidelines intervention were helpful in the improvement of the nurses' knowledge and practices for the prevention of port-A-catheter-related complications among oncology patients. Recommendations: Periodic educational programs regarding port-a-catheter care for nurses who provide care for patients connected to port-a-cath.