Postal Union Congress
The Postal Union Congress is the main international meeting of the Universal Postal Union, used to discuss various issues affecting international postal services, such as legislation, the political climate, and other strategic issues. The first congress was held in Bern, Switzerland in 1874, and was attended by delegates from 22 countries, most of them European. The meetings are normally held every four years, although they were cancelled during the two World Wars. Extraordinary Meetings can also be called outside the four-year cycle.
Delegates are usually presented with special albums of stamps by the other participating countries, to cover the period since the previous congress.
Quadrennial Congresses
| Number | Year | Location | Topic |
| 1st | 1874 | Bern, Switzerland | System of base rates developed. |
| 2nd | 1878 | Paris, France | Colour coding of postage stamps, international parcel post service proposed by Germany. |
| 3rd | 1885 | Lisbon, Portugal | Reply-paid postcards authorised. |
| 4th | 1891 | Vienna, Austria-Hungary | Rules about Paquebots. |
| 5th | 1897 | Washington, DC, United States | Cheaper international postage. |
| 6th | 1906 | Rome, Italy | Free postage for prisoners of war. |
| 7th | 1920 | Madrid, Spain | Meter mail and window envelopes approved. |
| 8th | 1924 | Stockholm, Sweden | |
| 9th | 1929 | London, United Kingdom | Postage paid franking approved, first airmail regulations. |
| 10th | 1934 | Cairo, Egypt | |
| 11th | 1939 | Buenos Aires, Argentina | Introduction of Fonopost. |
| 12th | 1947 | Paris, France | |
| 13th | 1952 | Brussels, Belgium | Approval of Aerogrammes. |
| 14th | 1957 | Ottawa, Canada | |
| 15th | 1964 | Vienna, Austria | |
| 16th | 1969 | Tokyo, Japan | |
| 17th | 1974 | Lausanne, Switzerland | |
| 18th | 1979 | Rio de Janeiro, Brazil | |
| 19th | 1984 | Hamburg, West Germany | |
| 20th | 1989 | Washington, DC, United States | |
| 21st | 1994 | Seoul, South Korea | |
| 22nd | 1999 | Beijing, People's Republic of China | |
| 23rd | 2004 | Bucharest, Romania | |
| 24th | 2008 | Geneva, Switzerland | |
| 25th | 2012 | Doha, Qatar | |
| 26th | 2016 | Istanbul, Turkey |
Extraordinary Congresses
| Number | Year | Location | Topic |
| 1st | 1900 | Berne, Switzerland | 25th anniversary of the UPU |
| 2nd | 2018 | Addis Ababa, Ethiopia | Sustainability of the postal sector |
| 3rd | 2019 | Geneva, Switzerland | Remuneration of small packets |