Abstract: Adequate cognition and understanding of the institution of civil juridical act nullity in the present state of the legislation, doctrine and judiciary practices obligatory requires the performance of an insight into the evolution of doctrinal concepts and representations which at different historical stages attempted to explain the essence and the juridical nature of nullity. In the framework of this study we will try to make a summative presentation of the nullity physiognomy in the context of various theories formulated throughout the consequent doctrinal evolution of this important institution of civil law.

Key-words: nullity, civil juridical act, sanction, non-existence