Self-expandable metal stents (SEMS) can be used for treatment of malignant biliary obstruction. Previously published literature has either reported on limited numbers of partially covered SEMS (PCSEMS) or groups their outcomes with fully covered SEMS (FCSEMS) in comparison to uncovered SEMS (UCSEMS). There is limited data focusing on outcomes and adverse events related specifically to PCSEMS. Furthermore, there is currently no consensus data on the optimum SEMS diameter to use. Our study aims to examine the clinical success, patency, and complications with regard to stent coating and stent diameter. All patients receiving a PCSEMS or an UCSEMS between 2009-2017 at a single academic center were retrospectively analyzed. Comparative analyses between different stent coatings (PCSEMS vs UCSEMS) and stent diameters (8 vs 10mm) were carried out. Factors compared included clinical success rates, patency durations and adverse events that occurred early (<30 days) or late (>30 days) from the date of SEMS placement. Adverse events included pancreatitis, cholecystitis, perforation, bleeding, cholangitis, stent occlusion and migration. There were 282 patients who had either PCSEMS or UCSEMS placement for malignant biliary obstruction identified. Baseline characteristics (gender, age) were similar between stent groups regardless of coating or diameter. Indications for stent placement were jaundice 225(80%) and cholangitis 57(20%) in the setting of pancreatic cancer 180(64%), cholangiocarcinoma 58(21%), and other malignancies 44(15%). Distribution of stent coating groups was: 214 PCSEMS (76%) and UCSEMS 68 (24%). Clinical success rates and patency duration were not statistically significant between PCSEMS and UCSEMS (96% vs 98%, P=0.34 and 264 vs 300 days, P=0.59). Adverse event rates were similar between both stent types with regard to early (9.4% PCSEMS vs 7.4% UCSEMS, P=0.59) and late (9% vs 10%, P=0.74) groups. Stent diameter groups examined included 174 (62%) 8mm stents and 106 (38%) 10mm stents; two 6mm stents were excluded. Stent diameter did not have an impact on overall clinical success (96% vs 99%, P=0.11), patency duration (142 days vs 181 days, P=0.54), or adverse event rates (16% vs 18%, P=0.96). Our data suggest PCSEMS have similar clinical success, patency duration and adverse event rates compared to UCSEMS in the treatment of malignant biliary strictures. Furthermore, despite the larger diameter, 10mm stents do not have a higher clinical success, patency duration, or complication rate then the 8mm stent diameter.