Background The benefit and timing of radiation therapy (RT) for patients undergoing a resection for pancreatic adenocarcinoma remains unclear. This study identifies trends in the use of radiation over a 10-year period and factors associated with the use of pre-operative radiation, in particular. Methods The Surveillance, Epidemiology and End Results registry was used to identify patients aged ≥18 years with pancreatic adenocarcinoma who underwent a surgical resection between 2000 and 2010. Logistic regression was used to identify time trends and factors associated with the use of pre-operative radiation. Results The overall use of radiation decreased with time among the 8474 patients who met the inclusion criteria. However, the use of pre-operative radiation increased from 1.8% to 3.9% (P ≤ 0.05). Factors significantly associated with receipt of pre-operative radiation were younger age, treatment in more recent years and having an advanced T-stage tumour. The 5-year hazard of death was significantly less for those who received pre-operative radiation versus surgery alone [hazard ratio (HR) 0.64, 95% confidence interval (CI) 0.55-0.74] and for those who received post-operative radiation versus surgery alone (HR 0.69, 95% CI 0.65-0.73). Discussion The use of pre-operative radiation significantly increased during the study period. However, the overall use of pre-operative radiation therapy remains low in spite of the potential benefits.