Background Arterial catheter placement for hemodynamic monitoring is commonly performed in critically ill patients. The radial and femoral arteries are the two sites most frequently used; there is limited data on the use of the axillary artery for this purpose. The aim of this study was to investigate the rate of complications from ultrasound-guided axillary artery catheter placement in critically ill patients. Methods A retrospective study at a tertiary care center of patients admitted to an intensive care unit who had ultrasound-guided axillary artery catheter placement during admission. Primary outcome of interest was catheter related complications, including bleeding, vascular complications, compartment syndrome, stroke or air embolism, catheter malfunction, and need for surgical intervention. Results This study identified 88 patients who had an ultrasound-guided axillary artery catheter placed during their admission. Of these 88, nine patients required multiple catheters placed, for a total of 99 axillary artery catheter placement events. The median age was 64 [IQR 48, 71], 41 (47%) were female, and median body mass index (BMI) was 26 [IQR 22, 30]. The most common complication was minor bleeding (11%), followed by catheter malfunction (2%), and vascular complications (2%). Univariate analyses did not show any association between demographics and clinical variables, and complications related to axillary arterial catheter. Conclusion The most common complication found with ultrasound-guided axillary artery catheter placement was minor bleeding, followed by catheter malfunction, and vascular complications. Ultrasound-guided axillary arterial catheters are an alternative in patients in whom radial or femoral arterial access is difficult or not possible to achieve.