**1. Introduction**

The right to appeal, in general, exists in several legal systems around the world responding to the two main characteristics of every human being. The first refers to the attitude of not settling for adverse decisions, which leads people to seek instruments to remediate these decisions, while the second is the possibility that every human being has to make mistakes and the need to correct these mistakes in decision-making acts that may have been mistaken [1].

Thus, an appeal is an instrument allowing for review of a decision made by a hierarchically higher instance aiming at its change or reversal. Appeals serve both as a process for correcting defective acts and as a process to find the actual and proper interpretation to a certain law or rule.

In the patent systems, appeals are primarily used to change or reverse an adverse decision by a first-instance patent examiner upon examination of the patentability of an application. This examination verifies compliance by the application with the legal provisions to become a patent. Among these provisions, attention is called to patentability requirements – novelty, inventive step, and industrial applicability – and patentability conditions – sufficiency of disclosure, clarity and/or support for the claims. When the patent examiner understands that any of these legal requirements and/or conditions is not met, the patent application is rejected.

Upon rejection of a patent application, a period for appeal against this decision begins. In the appeal procedure, a board of appeal or appeal division reviews the decision, taking the reasons that supported the first-instance administrative decision and the arguments of the parties into account, as to achieve a more proper decision for such case.

All patent offices have procedures for appeal against first instance administrative decisions taken by these offices, which are governed by specific laws, rules, and procedures. This chapter will study how appeals work in two of the main patent offices in the world, the European Patent Office – EPO and the United States Patent and Trademark Office – USPTO and in the Brazilian Patent Office – INPI, pointing out the main differences between them.
