The present study aims to underline the dynamic, versatile character of the patent procedure, with reference to both the European Patent Convention and the national law in Romania, France, Germany and Great Britain. These four national law systems have been deliberately chosen in order to illustrate how an essentially unitary procedure can be influenced by either the legal system in which it is applicable (romanic law or common law) or by the statal organisation (unitary or federal state). A particular attention was paid to the European Patent Convention that establishes a procedure that is operational at a european level, with obvious benefits for the patent granting procedure in terms of celerity and efficiency.