Recent studies indicate the existence of an information systems paradox: even the conceptually perfects, many become notorious implementation failures. This study has as main objective, understand the factors that contribute for successful or unsuccessful management information systems. Previous studies identified four main constructos that seem to be related with the success of these systems: (1) complexity, (2) user participation, (3) management support, (4) development team. Thus, we empirically test them existence thru the case study of exploitation and production segment of Petrobras -Petróleo Brasileiro S.A. management information system. The results indicate that the variables have power to explain system failure, indicating also management support and complexity as main causes and; that the adoption of this kind of system must be preceded of more formal evaluation.