Faced with the rapid development of electronic commerce in Mexico and in many parts of the world, it becomes increasingly necessary to rely on theoretical-empirical studies that include both qualitative and quantitative analysis, to help us understand the many faces of electronic trading activity. As SME’s are playing a very important role in the world economy, this research is aimed to analyze the relationship between the TOE model by Tornatzky & Fleisher (1990), and the competitiveness of manufacturing SME’s Electronic Commerce (EC) strategy. This research is divided into three parts: The first part reviews the Resource Based View (RBV); the TOE model for innovations’ adoption; and how concepts on competitiveness create a framework to support analysis on EC strategies’ competitiveness - and discusses the link between them. The second parte discusses the results of an exploratory empirical study aimed to identify key factors and variables involved in the success of the SME’s EC strategies. A Probit model was used to evaluate the relationship between the TOE factors and the ability of the company to develop effective EC strategies, preceded by a confirmatory factor analysis to specify the most important variables embedded in these three factors.