Objective:To retrospectively compare the efficacy and safety of ultrasound-guided thrombin injection (UGTI) with ultrasound-guided compression repair (UGCR) in patients with postcatheter-izational femoral arterial pseudoaneurysms (PSA). Methods: Thirty patients of this iatrogenic PSA [8 males, 22 females, average age (66. 5±5. 2) years] in our institution from 1997 to 2004 were retrospectively analyzed. Among them, 11 patients were treated with UGCR, 2 under continuous ultrasonographic (US) guidance and 9 under the guidance of femoral arterial bruit auscultation and dorsalis pedis artery palpation. Because UGCR was failed in 5 patients, consecutively 24 patients were treated with UGTI. Swine thrombin solution at a concentration of 200 U/ml was injected percutaneously using 22-25 gauge needles under color Doppler US. Demographics, clinical variables, pseudoaneurysm characteristics, and results of the 2 groups were compared by using Fisher’s exact test and Student’s t test. Results: The initial success rate of UGCR was 36. 4% (4/11) and the overall success rate was 45. 5% (5/11). Ten of 11 patients suffered from local pain during the compression, but there was no any complication in UGTI group. The average dose of injected thrombin was (180 + 82) U for PSA of a single loculus and (315±150) U for multiloculated PSA. The initial success rate of UGTI was 89.5% (17/19) and the overall success rate was 100% (24/24). Conclusion;UGTI offers a safe, quick and effective means of definitively treating femoral pseudoaneurysms and seems superior to UGCR. The amount of thrombin applied on our people seems smaller compared with others’ work. Methods: Thirty patients of this iatrogenic PSA [8 males, 22 females, average age (66.5 ± 5.2) years] in our institution from 1997 to 2004 were retrospectively analyzed. Among them, 11 patients were treated with UGCR, 2 under continuous ultrasonographic (US) guidance and 9 under the guidance of femoral arterial bruit auscultation and dorsalis pedis artery palpation. Because UGCR was failed in 5 patients, consecutively 24 patients were treated with UGTI. Swine thrombin solution at a concentration of 200 U / ml was injected percutaneously using 22-25 gauge needles under color Doppler US. Demographics, clinical variables, pseudoaneurysm characteristics, and results of the 2 groups were compared by using Fisher’s exact test and Student’s t test. Results: The Initial success rate of UGCR was 36. 4% (4/11) and the overall success rate was 45.5% (5/11). Ten of 11 patients suffered from local pain during the compression, but there was no any complication in The average dose of injected thrombin was (180 + 82) U for PSA of a single loculus and (315 ± 150) U for multiloculated PSA. The initial success rate of UGTI was 89.5% (17/19) and the overall success rate was 100% (24/24). Conclusion; UGTI offers a safe, quick and effective means of definitively treating femoral pseudoaneurysms and seems superior to UGCR. The amount of thrombin applied on our people seems smaller compared with others’ work.