Within the framework of the international regime on access to genetic resources, the FAO Treaty on access to plant genetic resources constitutes the main rule that the international community has adopted to guarantee food security in the world and to protect the rights that local communities and farmers have on certain vegetal varieties.For these purposes, the agreement establishes a Multilateral System of access which imposes on contracting parties a set of obligations designed to ensure the distribution of the benefits that may derive from accessing plant genetic resources.Contractual access forms are useful and necessary to guarantee the effectiveness of the multilateral system.