Background: paracentesis is a common invasive method for managing patients with ascites; but it is associated with many potential complications. Nurses play a crucial role in preventing theses complications by providing special care before, during and after the procedures. Aim of the study: To evaluate the effect of educational nursing guideline about paracentesis procedure care on nurses' performance. Methodology: Research design: A pre/ posttest quasi-experimental research design was utilized in the present study. Sample: A convenient sample of (40) nurses was included in this study. Setting: The study was carried out at the tropical medicine departments of Qena University Hospital and Qena General Hospital, Qena governorate, Egypt. Tools of data collection: Two tools were utilized to collect data, First Tool: Structured interviewing questionnaire covered 2 parts: First part: Demographic data of the nurses.  Second part included knowledge assessment sheet about paracentesis procedure. Second Tool: Observational checklist about paracentesis procedure. Study Duration: Data collection for this study was carried out through six months,   from the beginning of January 2019 till the end of June 2019. Results: The study results revealed that there was a highly statistical improvement in total level of nurses' performance regarding paracentesis procedures at post and follow up phases after implementation of educational guidelines than before, with (p < 0.001). Conclusion: The application of educational nursing guidelines about paracentesis procedure enriched nurses' knowledge and practice than before. Recommendations: Continuous nursing education about paracentesis procedure is recommended to upgrade the knowledge and skills of nurses, replication of the current study on a larger probability sample from different geographical areas to achieve generalizable results.Also it is important to investigate the effect of applying this educational nursing guideline on ascetic patients' outcome.