PURPOSE: To compare the feasibility and safety of US-guided right and left percutaneous transhepatic biliary drainage (PTBD). MATERIALS AND METHODS: Between March 1998 and May 1999, 32 patients underwent 36 US-guided right or left PTBD in referred order, alternatively. The causes of biliary obstruction were bile duct stone (n=2), bile duct carcinoma (n=10), carcinoma of the pancreas (n=9), GB carcinoma (n=7), metastasis to the porta hepatis (n=3), and carcinoma of the ampulla of vater (n=1). Technical success, procedure time, fluoroscopic time, and complications were evaluated. RESULTS: PTBD was successful in 94% of both right and left approach. The average procedure time was 9.7+/-3.8 min. in the right approach and 9.6+/-3.1 min. in the left approach, respectively (p=0.794). The average fluoroscopic time were 3.9+/-2.4 min. in the right approach and 3.8+/-2.2 min. in the left approach (p=0.892). A major complication, bile peritonitis, occurred in one of 16 patient with right-sided approach. Minor complications occurred in six right (2 hemobilia, 3 tube malfunction, 1 cholangitis) and three left (1 hemobilia, 1 fever, 1 cholangitis) PTBD. There were no significant difference in the complication rates between right and left PTBD (p=0.729). CONCLUSION: There were no significant differences in feasibility and safety in US-guided right and left PTBD.