The genus Passiflora contains more than 450 species, most of them native to the tropics and subtropics of the New World. While only 12 Passiflora species are cultivated, only 1 species, Passiflora edulis Sims., is highly commercialized for its fruits. Wild Passiflora species vary in their ecology and their morphology and many have an edible fruit. Because of their adaptations to different conditions, wild Passiflora are gene reservoirs for tackling many abiotic and biotic stresses of cultivated species such as for improving yield, vigor and resistance to diseases. Beneficial characters in wild species can be transferred to cultivar relatives by crossing, somatic hybridization or even genetic engineering. Wild relatives could also be used as rootstock for grafting. They could also present high contents of certain medicinal substances compared to the cultivated Passiflora species. The study and the preservation of wild Passiflora are essential to ensure the conservation of the genetic variability of the genus.