An initial assessment of the Mexican government’s implementation of the Model for the Performance Evaluation of Internal Control Organizations (MIDO) can reveal its actual influence on the organizational culture of those agencies. MIDO began in 2003 as an instrument to transform all federal monitoring agencies into effective, performance-driven organizations. It seeks to modify the behavior of internal control organizations in order to shift their rigid focus on control to a more flexible perspective. The idea is to allow them to take co-responsibility for the performance of the agencies they supervise. The author exposes a contradictory and paradoxical result of the program’s implementation: the “net organizational effect” is different from MIDO’s stated objective. The internal control organizations are not only adopting the discourse of performance, but also they are adapting it to fit their own purposes while keeping their traditional function of supervision intact. They have not internalized the co-responsibility culture, as MIDO proposes, despite accepting the discourse of performance evaluation.