Classification is a central concept in object-oriented approaches such as object-oriented programming, object-oriented knowledge representation systems (including description logics), object-oriented databases, software engineering and information retrieval. Nevertheless, research works on classification have often been carried out separately within these different approaches, and they have not always been precisely confronted and connected. The goal of the workshop was to confront these complementary viewpoints on classification, to exhibit and discuss commonalities and differences within these approaches.