Since the early 90 s, a political and economical line of thinking, favourable to the reduction of the State interference in the management of corporations, above all those related to the infrastructure segment and in micro-economic processes, has begun in Brazil. The deregulation, which could be observed in the second half of the decade, brought as a consequence the privatization of many State owned companies of different segments of infrastructure, among them those in the electric power distribution industry. This study was prepared coined on a data base containing financial and operational information from twenty three electric power distribution industries, which represented over seventy per cent of the energy sold in the country, corresponding to the periods between 1993 to 1995 (before privatization) and 1999 to 2001 (after privatization). The financial information was transformed into three performance variables and the operational information, into twelve strategic variables. From there, statistical techniques were utilized to adequate the study to the Porter s Typology, thereby permitting the industry analysis. With respect to this typology, the results obtained have permitted conclude that the model served for the analysis of this industry, under descriptive and explicatory aspects, with some reservations. The study concluded that changes have occurred in the corporations strategies, in the periods analysed, supplying indications to the identification of relevant competitive strategies, without, however, proving that the strategic groups had distinct performance. The study also did not confirm the basic hypothesis of Porter s Typology which praises that the company which adopts the generic strategy stuck-in-themiddle tends to presente performance below the industry average. In this study, the strategic groups focusing in differentiation, costs leadership, focusing on costs, stuck-in-the middle and differentiation presented, in this order, the best performance.