ABSTRACT.- The VegSyst model, initially developed for nitrogen (N) and irrigation recommendations for greenhouse-grown vegetable crops in southeastern Spain, was calibrated and validated for greenhouse tomato cultivated in soil in Uruguay (South America) for autumn and spring growing seasons. Additionally, the performance of the recalibrated VegSyst model was compared to the calibration for tomato grown in Almeria greenhouses of VegSyst model V3. Five tomato crops, three autumn and two spring crops grown in 2019, 2020 and 2021, were used for model calibration (Spring-19 and Autumn-20) and validation (Autumn-19, Spring-21 and Autumn-21). A major change to the existing VegSyst model (V3) was the incorporation of the Hargreaves-Samani equation adapted to plastic greenhouses to estimate ETo. The recalibrated VegSyst model accurately simulated dry matter production (DMP), ETc, and crop N and K uptake over time for autumn and spring growing seasons. Using the original VegSyst V3 calibration, acceptable results were obtained for DMP and N uptake. © 2023 The Authors. Published by Elsevier B.V.