The objective of this research is to determine from the point of view of strategic management the causes that Grupo Modelo is losing part of its market share in Mexico. In this sense, the question that triggered the writing of this article was: What are the causes of Grupo Modelo is losing part of its market share in Mexico? The hypothesis is that the strategies implemented by Grupo Modelo are not adequate for the industry in which it operates. These guidelines set the tone for the study to be conducted using the analytical method; so combining the elements of that instrument and the framework of Porter's Five Forces, the results that were obtained pointed out that the main cause of Grupo Modelo's loss of market to its main competitor, Heineken, is its advertising strategy.