Phlebotomy has practiced for centuries and still one of the most common invasive procedures in health care settings. Each step in this procedure affects the quality of the specimen and is thus important for preventing laboratory errors0, patient injury and even death. Unfortunately, phlebotomy poses risks for nurses and still common to carry out dangerous of practices known to increase the risk of needle-stick injury and transmission of blood borne diseases. The touch of a finger to verify the location of a vein before insertion of the needle increases the chance that a specimen may contaminated. This can cause false blood culture results, prolong hospitalization, delay diagnosis and cause unnecessary use of antibiotics. Clinical nursing errors in completing forms and identifying patients are common, costly and preventable. Other adverse effects for patients are common; they include bruising at the site of puncture, fainting, nerve damage and haematomas. The aim of the study was to investigate the effect of developed best practices nursing guideline in phlebotomy on patients’ safety and quality improvement. The research hypothesis, implement the developed best practices nursing guideline for phlebotomy will improve the patient safety and quality improvement. Method: A quasi- experimental design utilized in this study. A convenient sample of 80 patients divided equally into study and control groups, 40 patients each. The study conducted at all inpatient medical departments of the Main University Hospital at Alexandria, Egypt. Data was collected using Phlebotomy Nurses’ Performance Observational Checklist consists of three parts. Results showed that there was high incidence of phlebotomy local complications among the control group patients. From the investigators observations, this result may be due to lacking of nursing skills related to different aspects of phlebotomy. In addition, it may be due to inadequate basic education, unavailability of orientation and in-service training programs as well as postgraduate courses. In conclusion, applying the best practices nursing designed guideline for patient safety and quality improvement was effective in phlebotomy.Illustrated best practices nursing guideline should be available as a reference for health care settings recommended [Heba Abdel Mowla Ahmed, 2Lobna Mohamed Gamal Ali. Best Nursing Practices in Phlebotomy Patient Safety and Quality Improvement].