Since 1971, the UPU has encouraged young writers aged 9-15 to write letters on a given theme to win exciting prizes. The competition is an excellent way of making young people aware of the important role postal services play in our societies. It develops their skills in composition and their ability to express thoughts clearly. It also fosters enjoyment of letter writing and helps strengthen the bonds of international friendship.

The UPU's secretariat, the International Bureau, chooses a theme annually and publicises it. Participating countries then organize the competition at the national level through the Post, often with the support of the educational authorities and media. All entries must be submitted through the national Post. Each country chooses a national winner and submits them as the country entry to the UPU international competition no later than 30 April of the year in question.

• On average, two million children from more than 60 countries participate in the competition every year, with over one million alone from Viet Nam.
• Barbados and China jointly won first prize in 2011.
• Entries from China have won gold five time, in 1981, 1983, 1994, 1999 and 2011.
• Viet Nam won the 2010 competition after coming in second in 2009 and third in 1993, 1999 and 2004.
• Belarus won gold in 2003, silver in 2008 and 2010, and bronze in 2009.
• Ethiopia, Jordan, Malta and Mexico have each produced two top-prize winners.
• Entries from Ireland won the competition two years running in 1986 and 1987, the only country to do so.