The principle of non-retroactivity of the civil law has its fundament in ensuring the security of the civil circuit and in its compliance with the rights and legitimate interests of the subjects of law. After 1991, the Romanian legislator has chosen to constitutionalize the non-retroactivity of the law, stating a single exception, namely that of the criminal or administrative law more favourable. Therefore, the principle has acquired a mandatory feature, both for the legislator, for the law enforcement organs, as well as for other participants in the judicial circuit. In its turn, the Romanian Civil Code of 2011, by preserving the tradition of the Civil Code of 1864, expressly states the non-retroactivity of the civil law. Th us, the non-retroactivity is confi gured as a guarantee of the stability of the state of law, of the constitutionality, an essential guarantee of the constitutional rights and, especially, of the personal freedoms and safety.