Doñana marsh is one of the most important wetlands in Europe; however, it is under extreme human pressure. Remote sensing techniques have proved to be an effective method for modeling and monitoring biomass. The main objective of this project was to model the Doñana marsh biomass, to study the vegetation dynamics of the last 15 years and at the same time to predict the biomass in the future. This project consisted in four different steps: first, to mode the phenological curve, second, to calibrate the metrics of the phenological curve with the biomass production, third, to validate the model, and fourth, to map the biomass and analyze the main patterns of distribution and production. The results showed that it was possible to model the biomass production on the marsh using the NDVI; however it was clear that the high variability of the marsh made the process of modelling challenging. This variability is the result of a highly dynamic ecosystem that interplays water, soil, vegetation, and the presence of cattle. We hope this research can be a starting point to a more deeply research into the Doñana marsh biomass and be a tool for scientifically based management of the cattle in the marsh.