At the beginning of October, more than 9 000 participants including over 1 000 speakers from all over Europe and beyond gather together in Brussels for a programme of more than 300 working sessions, exhibitions and networking events on regional and local development. The programme is adapted every year to the specific context of the EU agenda. Participation to the event is free of charge.

Regions and cities are involved in the making of most EU policies. Sub-national public authorities in the EU are responsible for one-third of public expenditure (EUR 2 100 billion per year) and two-thirds of public investments (about EUR 200 billion), the latter often to be spent in accordance with EU legal provisions.

Back in 2003, the European Committee of the Regions, the EU’s assembly of regional and local representatives, invited Brussels-based local and regional representations to the European Union to open their doors to visitors simultaneously as part of a joint "Open Days" concept. Over the years, the initiative has developed into a key annual event involving the European Commission and other stakeholders. In 2016, the event was renamed "European Week of Regions and Cities", dropping the heading "OPEN DAYS". This was to avoid confusion with the annual "Open Doors / Open Day" Brussels-based events yearly organised in May by all EU institutions around Europe Day, as well as with similar events held by the Commission's Representations in the Member States on the same occasion.

The European Week of Regions and Cities is jointly organised by the European Committee of the Regions (CoR) and the European Commission’s Directorate-General for Regional and Urban Policy (DG REGIO). A call for partners is launched early in the year, usually in January. Following the call, over 200 partners from all over Europe are selected: regions and cities, mainly grouped into thematic consortia (Regional partnerships), companies, financial institutions, international associations or academic organisations. Partners have to organise seminars of common interest, often in the context of implementing European Structural and Investment Funds and other EU programmes.

The programme is organised around a key slogan and a number of sub-themes. The workshops or debates are organised by three categories of partners: 1/ Regional partnerships composed by European regions or cities; 2/ EU institutional partners; and 3/companies, financial institutions and local and European associations. Participants and speakers circulate between the different venues in Brussels: the conference venue(s), regional partners' venues, representations of Member States and other possible premises.

The audience is specifically interested in regional and urban policy, hence mostly officials at local, regional, national and EU level. The typical participant is from a regional or local administration, new to the event and is travelling to Brussels specifically.

In connection with the Brussels-based European Week of Regions and Cities, each Regional partnership is invited to organise a local event under the 'Europe in my region/city' initiative in the format of a citizens' dialogue or political debate and include a member of the European Committee of the Regions. The objective of these citizens' dialogues is to listen and report back directly on the discussions taking place in cities and regions. The local events are aimed at a wide range of participants including the general public, policy makers, experts, local and regional authorities, and the press, to raise awareness of the impact of EU policies in regions and cities.

Since its beginning, the impact of this event has been systematically evaluated. Participants have highlighted in particular the usefulness of information from the EU institutions and the networking with colleagues from other countries as being relevant to their professional management of EU funds. The importance of the event is also proven by its significant media impact. For years now, up to 300 print, radio, TV and online media journalists from all over Europe have come to Brussels to cover the event.