The accession of the United States and the European Union to the Madrid Protocol, on 2 November 2003 and 1 October 2004 respectively, was one of the two major innovations in international trademark law. With the inclusion of these jurisdictions in the protocol, most major commercial areas have joined the Madrid system. The Madrid Convention on International Trademark Registration Protocol – the Madrid Protocol – is one of two contracts that include the Madrid system for international trademark registration. The protocol is a deposit contract and not a substantial harmonization treaty. It provides a branding route for brand owners — individuals and businesses — to protect their trademarks in several countries by applying to a single office, in a language, with a royalty rate, in a currency. In addition, no local agents are required to submit the first application. For example, it is possible, under the protocol, to obtain an international registration on the basis of a pending trademark application, so that a trademark holder can, simultaneously or immediately after, file an application in a Member State, effectively apply for an international registration. In comparison, the agreement requires that the trademark holder already have an existing registration in a member jurisdiction, which can often take many months and sometimes years. Moreover, the agreement does not allow for the „conversion” of international records that have been „centrally attacked”.
On 31 July 2015, Algeria tabled its accession instrument and will accede to the Madrid Protocol on 31 October 2015. As Algeria is the last member of the Madrid system to comply, the protocol is now effective throughout the Madrid system.  Compliance with the convention or protocol includes membership of the Madrid Union. As of June 2019,[update] there are 104 members from 120 countries. The original treaty has 55 members, all of which are equally parties to the protocol (when Algeria acceded to the Madrid Protocol on 31 October 2015, all members of the Madrid agreement were also members of the Madrid Protocol and many aspects of the Madrid agreement no longer have practical effect). The term „Union de Madrid” can be used to describe the legal systems that are parties to the agreement or protocol (or both).  The protocol has been in force since 1996 and has 100 members, making it more popular than the agreement, which has been in force for more than 110 years and has 55 members.  The main reason why the protocol is more popular than the agreement is that the protocol has introduced a number of changes to the Madrid system that have greatly improved its usefulness for trademark holders.