Purpose : To evaluate the factors affecting procedure related technical difficulties of US-guided left sided PTBD and the complications involved in the use of this method. Material and Methods : We prospectively evaluated US-guided left PTBD in 26 patients with malignant biliary obstructions. The causes of underlying malignancy were bile duct carcinoma(n=10), adenocarcinoma of the pancreas(n=8), GB carcinoma(n=4), metastasis to the porta hepatis(n=2), duodenal carcinoma(n=1), hepatocellular carcinoma(n=1). We divided the procedure into four steps for the evaluation of technical difficulties, and we measured procedure time and fluoroscopic exposure time. And we evaluated the incidence of procedure related complications. Results:US-guided left PTBD was successful in all attempted 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 five transient hemobilia(19.2%), three tube malfunction(11.5%), and two fever(7.6%). Conclusion : US-guided left PTBD was easy to perform and a relatively safe method. The total procedure time was short, and as the radiologist becomes more experienced, this could be further reduced.