This report documents the updated version of the Partial Equilibrium Agricultural Trade Simulation (PEATSim) model developed by USDA’s Economic Research Service. PEATSim is a global model, covering 31 commodities and 27 countries/regions. The model, consistent with economic theory, provides a flexible country and commodity aggregation and accounts for cross-commodity linkages and interactions. The report includes a presentation and discussion of the structure and specific features of the revamped model, along with the theoretical underpinnings. It also documents an application of the model to illustrate its dynamic structure and to demonstrate the differential behavior.