Peripheral intravenous catheterization (PIC) is a routine invasive procedure in hospitalized patients, often leading to complications such as phlebitis. This inflammation of the vein is characterized by pain, erythema, and edema, among other symptoms, with various factors contributing to its development. In this study, we aimed to investigate the incidence, causes, and preventive measures of phlebitis in ICU patients with peripheral IV catheters. Data was collected from 785 adult patients hospitalized in the ICU from December 2022 to September 2023, focusing on demographics, catheter specifics, and medication administered. The study revealed a 9.9% incidence of phlebitis, with factors such as gender, age, catheter gauge, duration of use, insertion site, and drug class influencing its occurrence. Notably, antibiotics were associated with the highest incidence of phlebitis. These findings underscore the importance of continuous monitoring and improvement in catheter management practices to reduce phlebitis rates in critically ill patients.