The Union of Czech Mathematicians and Physicists celebrated the 150th anniversary of its foundation. On the occasion of this anniversary on March 28, 2012, the Union at Karolinum, the seat of the Charles University, a festive ceremony, attended by outstanding personalities headed by the President of the Czech Republic Vaclav Klaus. The Union was founded in 1862 as the Association for Free Lectures in Mathematics and Physics. From the beginning, its goal was the improvement of the teaching physics and mathematics at schools on all levels and of all types and further, to support and promote the development of those sciences. As a consequence of patriotic efforts, the Association was enlarged in 1869 into the Union of Czech Mathematicians and Physicists. In the early 1950s, the Union had to transfer its property to the newly established Czechoslovak Academy of Sciences (CSAV) and it became a learned society affiliated with CSAV. The mathematical part of its library became the basis of the library of the Mathematical Institute of CSAV, and is located there at present. Today, the Union has about 2,800 members. The Union itself, or in collaboration with universities and research institutes, organizes national as well as international conferences, symposia, seminars, and Summer or Winter schools. The Union follows the teaching of mathematics and physics in schools and proposes improvements. It encourages talented students and participates in the organization of the Mathematical and Physical Olympiad and other student competitions. Czech Post has issued a stamp commemorating the 150"i Anniversary of the Foundation of the Union of Czech Mathematicians and Physicists. and Martina Bečvárová.