PURPOSE: To evaluate the factors affecting procedure related technical difficulties of US-guided left sidedPTBD and the complications involved in the use of this method. MATERIAL AND METHODS: We prospectively evaluatedUS-guided left PTBD in 26 patients with malignant biliary obstructions. The causes of underlying malignancy werebile duct carcinoma(n=10), adenocarcinoma of the pancreas(n=8), GB carcinoma(n=4), metastasis to the portahepatis(n=2), duodenal carcinoma(n=1), hepatocellular carcinoma(n=1). We divided the procedure into four steps forthe evaluation of technical difficulties, and we measured procedure time and fluoroscopic exposure time. And weevaluated the incidence of procedure related complications. RESULTS: US-guided left PTBD was successful in allattempted cases. The average procedure time and fluoroscopic exposure time involved were 14.2 min. and 5.5 min.,respectively. From the first step to the fourth step, the average time required was 4.4 min, 2.3 min., 1.9 min.,5.6 min., respectively. One major complication involved sepsis(3.8%), and ten minor complications including fivetransient hemobilia(19.2%), three tube malfunction(11.5%), and two fever(7.6%). CONCLUSION: US-guided left PTBDwas easy to perform and a relatively safe method. The total procedure time was short, and as the radiologistbecomes more experienced, this could be further reduced.