With the emergence of the internet, the e-commerce grows on daily basis, in Brazil and in the world. In 2007 was still very low by Brazilian trade firms, even considering only firms with 20 or more employees. Only 855 firms adopted this practice in a total of 38.339 firms. The set up of this kind of innovation allows reduction of transaction costs, but, in the other hand, it demands logistics and information technology upgrades, and also qualified personnel. Theses improvements could dealt by public policies. The current studied developed a pioneering evaluation of the effects of e-commerce in the Brazilian economy. More specically, the effects of adoption of this kind of innovation in the productivity of wholesale and retail firms were analyzed. The studied followed an econometric methodology that tries to control the possible effects of endogeneity and self-selection bias. In other words, it tries to control the possible bias caused by the fact that the choice of adoption or not e-commerce might be influenced by the productivity. The study used microdata of the 2007 Annual Trade Survey (Pesquisa Annual de Comércio), by the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografica e Estatística, the Brazilian nacional statistics agency). The methodology was used by Bertschek, Fryges and Kaiser (2004) to evaluate the impact of business-to-business e-commerce on the productivity of German firms.