Recently a multidisciplinary investigation program on the systematics of Annonaceae was started at Utrecht with special emphasis on the Neotropics. This project will be carried out largely within the framework of the UNESCO-project Flora Neotronica. The first goal is to provide a modern classification of the family as a whole, the second is the publication of a series of monographs for Flora Neotropica. The project has been planned and started in close consultation with leading botanists on the Neotropical flora. The Annonaceae are a family of pantropical distribution with between 2000 and 2500 species in ca. 130 genera as presently understood. In the Neotropics the family is represented by ca. 750 species and 35 genera. It is a family of trees, shrubs, and lianas. Its place is within the order of the Magnoliales and its supposedly closest relative is the family of the Myristicaceae. The Annonaceae, although generally considered primitive in many features, nevertheless offer a number of specialized features as well This makes it a promising object using various kinds of comparative morphological, karyological, and anatomical data. Besides, many species are of medicinal or commercial value, such as various species of Annona and Rollinia, the fruits of which are commonly eaten in most countries of Central America and South America; the Soursop (Annona muricata) is widely cultivated throughout the tropics.