In patients requiring long-term hemodialysis for chronic kidney disease, an arteriovenous fistula is the preferred mode of hemodialysis access over synthetic arteriovenous graft or hemodialysis catheters. The National Kidney Foundation recommended in their Kidney Dialysis Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines that the creation of an autogenous arteriovenous fistula should initially be sought whenever possible. In 2003, a program named the Fistula First Breakthrough Initiative was initiated in the U.S. to increase the use of arteriovenous fistula for hemodialysis and to ultimately surpass the goal of 50% fistula use in incident and 40% fistula use in prevalent hemodialysis patients per recommendation by KDOQI Guidelines. While this goal was achieved, the encouraged creation of arteriovenous fistulas saw a rise in fistulas that failed to mature. Researchers have focused on developing strategies to optimize fistula maturation. Studies have revealed that the presence of stenoses and accessory draining veins may contribute to unsuccessful fistula maturation. Endovascular treatment, including balloon angioplasty and accessory vein embolization, aim to correct anatomical factors that negatively affect the maturation process. This article reviews the techniques and outcomes of endovascular treatment in the management of immature fistulas.