Background: A peripheral intravenous cannula is an essential tool for delivering drugs, blood products, and nutritional fluids to patients intravenously. At least 90% of all patients who enter the medical environment for care have some form of intravenous therapy. Giving medications through an intravenous cannula can be complicated due to its association with serious infections.Aims of the study: The study aimed to evaluate the effectiveness of the intervention program on the practices of the nursing staff towards preventing peripheral intravenous cannula complications in Al-Diwaniyah Teaching Hospital.Methodology: A quasi-experimental design was carried out at the medical and surgical departments of Al-Diwaniyah Teaching Hospital for the period 22 \ December \ 2020 to 1 \ May \ 2021. A non-probability (purposive) sample of 60 nursing staff who worked in the surgical and medical departments was selected, and they were divided into two groups, the study group and the control group. The study sample consisted of (30) nurses who were exposed to the intervention program, while the control group consisted of (30) nurses were not exposed to the nursing interventional program. To measure the effectiveness of the intervention program on practices of the nursing staff, the researcher used a practice checklist that included (12) items related to preventing peripheral intravenous cannula complications. To analyze the results, descriptive statistics (frequencies, percentage, arithmetic mean, standard deviation) and inferential statistics (ANOVA, t-test) were used.Results: The pretest results showed that there was no significant difference between the study group and the control group (Mean of study group=1.25 versus Mean of control group=1.21) In the posttest, the results showed a significant improvement in the practices of the study group compared to the control group (Mean of study group=2.46 versus Mean of control group=1.28).Conclusion: The study concluded that the educational program has a positive effect on the nursing staff's practices regarding Prevention of Peripheral Intravenous Cannula Complications in Diwaniyah Teaching Hospital.Recommendations: The study recommended the necessity of activating the guidelines for peripheral intravenous cannulation in health institutions, and conducting future research to improve the knowledge and practices of the nursing staff about the prevention of complications of the peripheral intravenous cannula.