Intravascular device infections could be serious complications with significant contributable morbidity and mortality. The aim of this prospective clinical study is to demonstrate the infection rate related to peripheral arterial catheters and their clinical significance in neurosurgical intensive care unit (ICU) patients. After removal, all arterial catheter tips were cultivated by semiquantitative method and clinical data were collected. During a period of two years, 186 arterial catheters were placed in 105 neurosurgical ICU patients. In 6 cases (3.2%) infection was presumably related to the arterial catheter. The rate of such probable catheter related infections was found to be 5/1000 catheter days. The isolated microorganisms were: Methicillin resistant Staphylococcus epidermidis (MRSE) in 4 cases, Corynebacterium species and Candida albicans each in one case respectively. Thirteen cases (7.0%) were interpreted as contamination and one as colonization. An association was found between the presence of infection from different sources and significant bacterial growth on the catheter. Patients with positive catheter culture had a significantly longer ICU stay, more cumulative catheter days, and a higher mortality rate than those with sterile catheters. We can conclude that the rate of probable peripheral arterial catheter related infection is low. A higher mortality rate in patients who experienced probable catheter related infection does not seem to be a consequence of the aforementioned infection. A more suitable explanation would be that patients with nosocomial infections and higher mortality risk have prolonged ICU stays. There is an increased chance of developing a catheter related infection in those patients who have more cumulative catheter days.