Background: The incidence of acute pancreatitis (AP) is characterized by circannual and geographical variation. The aim of this study was to describe seasonal variation and trends in hospitalizations for AP in the USA with respect to AP etiology.Methods: The Nationwide Inpatient Sample data (2000–2016) from the Healthcare Cost and Utilization Project were used. The study population included all primary hospitalizations for AP. Biliary AP (BAP) and alcohol-induced AP (AAP) were distinguished by diagnostic and procedural ICD codes. Seasonal trend decomposition was performed. Results: There was a linear increase in annual incidence (per 100000 population) of AAP in the USA (from 17.0 in 2000 to 22.9 in 2016), while incidence of BAP, equaled 19.9 in 2000, peaked at 22.1 in 2006 and decreased to 17.4 in 2016. AP incidence demonstrated 18％ annual incidence amplitude with summer peak and winter trough, more prominent in AAP. In 2016, within AAP, the highest incidence (per 100000 population) was noted among African-Americans (up to 50.4), followed by males aged 56–70 years (26.5) and Asians of low income (25.5); within BAP, above the average incidence was observed in Hispanic (up to 25.8) and Asian (up to 25.0) population. The most consistent and rapid increase in AP incidence was noted in males aged 56–70 years with an alcoholic etiology (average 6％ annual incidence growth). Conclusions: The incidence and annual trends of AP vary significantly among demographic and socioeco- nomic groups and this knowledge may be useful for the planning of healthcare resources and identifica- tion of at-risk populations.