Background: Arterial puncture, for obtaining an analysis of blood gas, is an interventional procedure often performed in emergency departments and intensive care units. Our goal in this study is to compare the traditional method and ultrasound (US) guided method in radial artery puncture for blood gas analysis in septic shock patients. Methods: This is a prospective, randomized study. Septic shock patients over 18 years of age who needed a radial artery puncture sample for blood gas analysis were included in the study. Patients with local infection or trauma at the puncture site, arteriovenous fistula, vascular graft, coagulopathy, Allen test positive and those who did not want to participate in the study were excluded. Patients were randomized into 2 groups: radial arterial puncture obtained through an US guided technique or radial arterial puncture by conventional method. The main outcomes are success at the first entry, the number of attempts and time to success after enrollment. Results: 50 eligible patients were randomized into two groups. The success rate of the first puncture in the ultrasound group and the palpation group was 80% and 42%, respectively. The number of attempts and time to success significantly increased in conventional group. Conclusion: The US-guided method has been found to be more successful in terms of success at the first entry, number of attempts, time to success compared to the conventional method.