The purpose of this article is to address main clinical issues and the way to assess right ventricular (RV) function of adult patients with transposition complexes and systemic RV failure. Echo, cardiopulmonary exercise test, radionuclide ventriculography, cardiac magnetic resonance imaging, multislice computed tomography, and cardiac catheterization may be performed in adult patients with transposition complexes to evaluate clinical status and RV function. Echo is an everyday clinical tool that can give valuable information on RV function, tricuspid regurgitation, concomitant lesions, or postoperative complications. Cardiac magnetic resonance is the gold standard in the estimation of RV volumes and function. Cardiopulmonary exercise test can provide objective evaluation of patients' clinical status. Other imaging modalities are useful when appropriate. In conclusion, for all transposition complexes adult patients should undergo a regular follow-up to recognize early signs of systemic RV failure.