The evaluations of the Programme for International Student Assessment (PISA) demonstrate that Peru has serious shortcomings in mathematics, result that is harmful to the formation of future engineers. For it before this problems the Institute of Sciences and Humanities (ICH) promotes the Realistic Mathematical Education (RME) in the pre university education. And before the need to evaluate some achievements of the ICH, the present studies takes as a finality to identify relation between the application of the principles of the RME and the mathematical self-efficacy in a sample of 60 pre university students candidates to the engineering careers (28 men (45.9 %) and 32 women (54.1 %)) (Mage = 17.84, SD = 1.76). The results demonstrate that the application of the principle of guided reinvention and the principle of interconnection is related by them with the mathematical self-efficacy; but only the principle of interconnection predicts to the mathematical self-efficacy.