Background/Aims: Endoscopic uncovered metal stent (UMS) placement has been widely performed for unresectable hilar malignant biliary stricture (UHMBS). Two stenting methods are used for the two bile duct branches: side-by-side placement (SBS) and partial stent-in-stent placement (PSIS). However, it remains controversial whether SBS or PSIS is superior. This study aimed to compare SBS and PSIS in UHMBS cases with UMS placement in two branches of the IHD. Methods: This retrospective study included 89 cases of UHMBS treated with UMS placement through the SBS or PSIS technique using endoscopic retrograde cholangiopancreatography at our institution. Patients were divided into two groups, SBS (n= 64) and PSIS (n= 25), and compared. Results: Clinical success was achieved in 79.7% and 80.0% in the SBS and PSIS groups, respectively (p= 0.97). The adverse event rate was 20.3% and 12.0% in the SBS and PSIS groups, respectively (p= 0.36). The recurrent biliary obstruction (RBO) rate was 32.8% and 28.0% in the SBS and PSIS groups, respectively (p= 0.66). The median cumulative time to RBO was 224 and 178 days in the SBS and PSIS groups, respectively (p= 0.52). The median procedure time was 43 and 62 min in the SBS and PSIS groups, respectively, which was significantly longer in the PSIS group (p= 0.014). Conclusions: No significant differences were noted in the clinical success rate, adverse event rate, time to RBO, or overall survival between the SBS and PSIS groups, other than the significantly longer procedure time in the PSIS group.