Background and Aims: Patients with biliary obstruction caused by adenocarcinoma of the pancreas head may require bile duct decompression to treat symptomatic cholestasis and/or permit systemic chemotherapy. ERCP with biliary stent placement is the preferred intervention in such cases. The primary aim of this study was to determine what proportion of patients with surgically unresectable pancreatic adenocarcinoma undergo ERCP and whether this proportion has changed over time. Methods: We used Surveillance, Epidemiology, and End Results (SEER)-Medicare–linked data to identify a cohort of individuals diagnosed with adenocarcinoma of the pancreas head between December 31, 2000 and December 31, 2015 and who did not receive pancreas surgery. ERCP use was measured in the 30 days before and after cancer diagnosis. Additional covariates of interest were extracted for multiple variable analysis. Results: A total of 14,810 patients met study inclusion and exclusion criteria. Of them, 53% (7034/14,810) underwent ERCP within 30 days of cancer diagnosis. The proportion of patients who underwent ERCP declined from 57% in 2001 to 46% in 2015 (P for trend < .001). Among those who underwent ERCP, the mean number of ERCPs performed per patient over the year after diagnosis declined from 2.3 (standard deviation, 1.6) in 2001 to 1.8 (standard deviation, 1.1) in 2015 (P < .001). Despite decline in ERCP use, adjusted 1-year survival increased over time. Conclusions: In a SEER-Medicare population between 2001 and 2015, both the proportion of patients with unresectable pancreas cancer who underwent ERCP and the mean number of ERCPs per patient decreased over time. Survival improved over time despite decreased use of ERCP.