Controversy exists over the need for unilateral versus bilateral stent placement in patients with malignant obstruction at the biliary hilum. Placement of bilateral uncovered self-expanding metal stent (UCSEMS) at this location is technically challenging, and generally associated with lower rates of procedural success. Serial insertion of side-by-side UCSEMS may be especially difficult when simultaneous deployment is not possible using larger stent delivery catheters. In this single-center, retrospective case series of all patients who underwent bilateral placement of uncovered WallflexTM biliary stents between July 2008 and July 2014, we evaluate the feasibility, technical success, and safety of patients undergoing serial insertion of bilateral UCSEMS using the 8 Fr WallflexTM biliary system for malignant hilar obstruction. A total of 17 patients were included. Primary cholangiocarcinoma, Bismuth IV, was the most common diagnosis. Mean procedure time was 54.4 minutes. Overall procedural technical success was achieved in 17/17 patients. Stricture dilation was necessary prior to WallflexTM insertion in 8/17 patients (47.1％). Transpapillary extension of two stents was performed in all patients. There were no cases of stent deployment malfunction, or inability to insert or deploy the 2nd stent. Nine of 17 patients (52.9％) required inpatient hospitalization following ERCP; the most common indications were abdominal pain and need for IV antibiotics. There was one case of ERCP-related cholangitis otherwise; there were no other major complications. Bilateral, serial insertion of UCSEMS using the 8 Fr WallflexTM biliary system in malignant hilar obstruction is feasible with an excellent technical success profile. Using this device for side-by-side deployment of UCSEMS appears to be safe in the majority of patients.