In Israel, scarcity of water, high input prices, and market competition limit the number of orchard crops that can be grown profitably. Our approach to the further development of the horticultural industry in the dry regions of Israel—the Negev and Judean deserts—is thus to establish new crops that will demand high prices in the export markets (Mizrahi and Nerd 1996). To this end, about 40 species of rare or wild fruit trees were introduced by us into these dry regions in a number of locations that differed in terms of soil, water, and climate (Nerd et al. 1990; Mizrahi and Nerd 1996). Emphasis was placed on candidates of the Cactaceae because of their high water-use efficiency (5–10 times higher than that of most conventional crops), resulting in low water requirement (Nobel 1988, 1994). The high water-use efficiency of cacti is provided by their unique photosynthetic pathway—crassulacean acid metabolism (CAM). In CAM plants, the stomata open and CO 2 uptake takes place during the night when evaporation is low. Among the Cactaceae, there are about 35 species that have a potential for cultivation as fruit, vegetable, or forage crop species (Nobel 1994; Mizrahi et al. 1997). Starting in 1984, we have introduced, for investigation as potential crop species, 17 members of the subfamily Cactoidae (Nerd et al. 1990; Mizrahi and Nerd 1996). Among these, four climbing (epiphytic) species and one columnar species have already been planted as commercial crops, and their fruits are being exported successfully to European markets as exotic fruits from Israel. The main reasons that these crops have made their way onto the market within so short a time after introduction are their precocious early yield-ing (three to four years after seeding or one to three years after propagation from cuttings) and their accept-ability in the markets. At present, our studies are aimed at examining the environmental adaptations of the species and their reproductive biology mode and at developing appropriate agrotechnological practices. In addition, a breeding program accompanied by cytological and molecular studies is being carried out in order to develop improved clones for cultivation. This review is divided into two parts. The first part deals with the climbing cacti of the genera Selenicereus and Hylocereus and the other with the columnar cactus Cereus peruvianus. CLIMBING (EPIPHYTIC) CACTI Taxonomy We collected wild or cultivated types of climbing cacti from a variety of sources—amateur cactus lovers, growers, botanical gardens, and backyards. We very soon realized that there is tremendous confusion about the taxonomic identity of these cacti: accessions with the same name were found to be of different species. We are currently applying cytological and molecular techniques to determine the proper taxonomic identities of the species that we have introduced (Lichtenzveig 1997). These species belong to at least to two different genera, Selenicereus and Hylocereus. From the genus Selenicereus we will elaborate here only on one species S. megalanthus, currently grown in Israel and in Colombia, where it is known as yellow pitaya (Hunt 1989; Barthlott and Hunt 1993), Acces-sions of S. megalanthus were introduced by us as H. triangularis or H. undatus and were later classified as S. megalanthus (Weiss et al. 1995; Mizrahi et al. 1997). We have 37 selected clones from this species. From the genus Hylocereus, we have introduced the following species, some with a number of clones (Table 1): H. undatus, H. polyrhizus, H. purpusii, H. ocamponis, and H. costaricensis (Britton and Rose 1963; Barthlott and Hunt 1993). In addition, we have introduced some promising unidentified clones of Hylocereus (Hylocereus sp.), the best of which was designated as 10487. Of these species, only the ones that are currently being grown in Israel for export are described in this paper, as follows: H. undatus, H. polyrhizus, and Hylocereus Reprinted from: Perspectives on new crops and new uses. 1999. J. Janick (ed.), ASHS Press, Alexandria, VA.