The Middle Magdalena Valley region - VMM, Colombia, is one of the areas with the densest population and industrial growth. To heed the growing water demand it is necessary to raise the knowledge in regards to underground water resources to achieve a sustainable use of those. While the amount and availability of underground water in the region is generally better characterized and understood due to hydrogeological studies made by national and regional environmental authorities, the issue of quality, and more specifically the processes and hydrogeochemical evolution of underground water, it is poorly studied and understood. Agricultural, industrial and mining-energetic development in the area, are activities that could potentially alter the quality of underground water. The VMM is one of the areas in the country with the greatest prospect for the use of hydraulic fracturing as a technique for exploration and production of non-conventional reservoirs YNC and hypothesis derived from different studies associate pollution and conflicts in underground water with the development of this type of projects.**Therefore, this research was aimed to identifying the main processes responsible for the quality and hydrogeochemical evolution of underground water through the use of multivariate statistical techniques (Factor Analysis, Principal Component, and Conglomerates). They were compiled and analyzed all the underground water samples reported in the Environmental Impact by oil companies which explore and exploit hydrocarbons in the area of study for the period 2010-2014. As a result, hydrochemical classification of underground water was established, the processes controlling its composition, and a conceptual model was proposed to explain the geochemical evolution in the area of study.**