Reaching consumers effectively is one of the main challenges facing businesses, particularly those in retail. The latter is due to advances in information technology and the phenomenon of social media has given rise to new digital and asynchronous tools to increase dialogue between businesses and consumers. This study applied the Confirmatory Factor Analysis and Structural Equations Modeling to analyze data collected from a questionnaire applied to 421 marketing managers in Medellín's retail sector (Colombia). This study uses the Technology Acceptance Model - TAM to identify the factors that promote the adoption of social media marketing in retail companies. Identifying these factors facilitates the design of strategies to take advantage of this form of marketing to retain current customers and reach potential customers. This study highlights that the usefulness of social networks does not depend on the perception of how easy or difficult it is to use them as some authors have pointed out. Furthermore, it allows reaffirming the positive influence of Trust on the Perceived Usefulness construct and Perceived Ease of Use, which promotes the adoption of marketing in Social Media.