Fruit tree genetic resources in Malaysia consist of cultivated and wild species. The cultivated fruit trees number more than 100 species of both indigenous and introduced species. Among these fruits, some are popular and are widely cultivated throughout the country while others are less known and grown in small localized areas. The latter are the under-utilized fruit species. Apart from these cultivated fruits, there is also in the Malaysian natural forest a diversity of wild fruit tree species which produce edible fruits but are relatively unknown and unutilized. Many of the under-utilized and unutilized fruit species are known to show economic potential. Collection and evaluation of some of these fruit tree genetic resources have been carried out. These materials are assessed for their potential as new fruit trees, as sources of rootstocks for grafting and also as sources of germplasm for breeding to improve the present cultivated fruit species. Some of these potential fruit tree species within the genera Artocarpus, Baccaurea, Canarium, Dimocarpus, Dialium, Durio, Garcinia, Litsea, Mangifera, Nephelium, Salacca, and Syzygium are highlighted.