PURPOSE : To evaluate the utility and safety of drainage catheter installation for psoas/iliopsoas muscle abscesses using a one-step technique under the guidance of real-time computed tomography (CT) fluoroscopy. MATERIALS and METHODS : Ten psoas or iliopsoas muscle abscesses in 7 patients that were treated with percutaneous drainage were included in this study. All drainage procedures were carried out using a one-step technique under real-time CT fluoroscopic guidance. RESULTS : The drainage catheter insertion was performed successfully with the one-step technique in all lesions. Improvements in the patients’ symptoms and blood test results were seen after the drainage procedure in all cases. In addition, postoperative CT scans demonstrated that the abscesses had reduced in size or disappeared in all but one patient, who was transferred to another institution while the drainage catheter was still in place. No major complications were seen in any case. CONCLUSION : The one-step procedure is simple to perform. The percutaneous drainage of psoas or iliopsoas muscle abscesses with the one-step technique under real-time CT fluoroscopic guidance is accurate and safe. Moreover, compared with the two-step technique the one-step procedure results in a shorter drainage procedure and exposes the patient and operator to lower amounts of radiation