Background: The aim of this study was to monitor the evolution of the incidence of pancreatic cancer in Denmark over 70 years. We also compared registrations of pancreatic cancer in a nationwide population-based database, the Danish Cancer Registry, and a clinical database, the Danish Pancreatic Cancer Database, in 2012–2013. Material and methods: Registrations of pancreatic cancer from the Danish Cancer Registry over 1943–2012 were used to calculate age-specific incidence rates per 100 000 person years by sex and age in 5-year period, weighted by the Segi World Standard Population for age standardization. We used absolute numbers from the Cancer Registry and the Pancreatic Cancer Database, including distribution of topography of cancers registered in 2012–2013, to compare registration in the two data sources. Results: The incidence rates of pancreatic cancer among Danish men increased until 1968–1972, when a decrease was observed until the mid-1990s. A similar peak was observed in women a decade later but generally at lower incidence. After the mid-1990s, the incidence rates for both sexes increased until the end of the study period. In our comparison of registrations in the Cancer Registry and the Pancreatic Cancer Database in 2012–2013, we found that 29% of the incident cases registered in the Cancer Registry were not in the Database; and 11% of the incident cases registered in the Database, were not registered in the Cancer Registry. Conclusions: The incidence of pancreatic cancer increased steadily during the last 20 years of our study period in both sexes. The differences in registration of incident cases in the Cancer Registry and in the Pancreatic Cancer Database indicate underreporting of incident cases of pancreatic cancer in Denmark. The magnitude of this underreporting cannot be estimated based on this data.