In the doctrine of specialty there have been outlined three theories concerning the juridical nature of accepting an offer. In a bonus theory the acceptance represents a juridical action. It has been reasoned that this declaration of will is not subject of notification. Only in this way one can explain why the tacit acceptance, or in some cases, the implementation of the offer produces juridical effects. Another proposed criterion is to determine the efficiency character of the acceptance – juridical or practical. The supporters of this theory declare that the acceptance is subordinated to an efficiency practice, the one to be known to the offerer, and not juridical on which the concluding of the contract depends. The contract can be implemented only if the offerer gets to know of the acceptance. According to another theory acceptance is a subjective right, part of the category of subjective rights and would be considered to come into the accepter’s patrimony by virtue of an accord carried out by emission of the offer. A critisizable solution, both by the hypothetic character of the realized accord and due to the fact that the offerer cannot a passive subject in a potestative law. The third theory, I appropriate, is a unilateral act. The effects produced by acceptance are identical with those of the civil juridical act – birth, modification and extinction of juridical relations – respectively acts by which rights and obligations are transferred, acts of renunciation of rights and those of acceptance of rights and obligations. As well, being a declaration of will it can be vitiated, resulting in the nullity or anullability of the agreement, specific sanctions of juridical acts.