This chapter aims to describe the main aspects related to the creation of an arteriovenous fistula. The criteria for assessing the vascular network are discussed with a focus on the appropriate selection of the artery and vein. The different types of fistula will also be introduced, namely radiocephalic, brachiocephalic, and brachiobasilic, emphasizing the indications and particularities of each technique. Finally, the maturation process is analyzed, including the hemodynamic and structural changes needed to guarantee a functional and permeable access, suitable for the requirements of hemodialysis treatment.