We live now at the time of an extraordinary development of museums. They have become one of the most important elements of the cultural life and a part of gigantic tourist programs. Many new museum structures have been recently designed and erected as well as some very original annexes which have been added to the ancient edifices. Most talented architects are engaged in this branch. Several endeavours have been made to compose a classification of museum buildings, so far not quite satisfactory. The author of the article, curator of the Czartoryski Museum in Cracow and lecturer at the Jagiellonian University, proposes his own classification. First museum buildings in Europe originate from the turn of the eighteenth century. Almost all of them followed the examples of famous edifices of antiquity, especially the Parthenon of Athens and the Pantheon of Rome. The third pattern was in a long antique portico called stoa. The models of a Renaissance palace or a Baroque church were taken over by the architects about the middle of the nineteenth century. Most spectacular examples of this style can be find in Munich: the Alte Pinakothek and the Bayerisches Nationalmuseum. Then, at the beginning of the twentieth century, the Bauhaus promoted a distinct change of style which was adopted in many countries, particularly in the USA. During the Second World War and the following period of the 'cold war' museum buildings were transformed into fortresses or bunkers of reinforced concrete, usually with deep shelters beneath. Museum structures were often designed in form of a pyramid, a half-ball, sphere or even a flying saucer. The bunker style was followed by a seemingly opposite style of a transparent building, totally covered with glass, but also provided with deep underground shelters. A short-lived fashion of surrealism in museum designing can be observed in museum-mausoleum of Salvador Dali in Figueres. Soon after there came the idea of a building-sculpture called deconstructive, with the most spectacular example of the Guggenheim Museum in Bilbao designed by Frank O. Gehry. The architects of young generation have been seized by a new passion - that of zoomorphic and biomorphic forms. They are derived from nature itself, particularly from the world of the see monsters like whales, dolphins, jelly-fish; from animals like turtles or armadillo as well as birds and insects. The Milwaukee Art Museum by an outstanding architect Santiago Calatrava may serve as an example. Entirely original and standing apart from this trend is the building of the Jewish Museum in Berlin – a masterpiece of Daniel Libeskind. In Poland there is in fact only one quite modern museum building – the Centre of Japanese Art and Technology in Cracow designed by Arata Isozaki. In the presented classification it is a hybrid - half bunker, half transparent.