Vascular ultrasound has been proven to be effective in the assessment of hemodialysis fistulas providing noninvasive diagnostic work-up of vascular morphology and hemodynamics. The most common reason for hemodialysis fistula failure is thrombosis due to stenosis. Therefore, early identification of stenosis is essential to avoid complications. Ultrasound-based identification of hypoechoic plaques and intimal proliferation helps to reach therapeutic decisions. An estimation of the grade of stenosis is also feasible. An occlusion rate of up to 45% due to reduced blood flow justifies follow-up examinations. Due to frequent puncture of the fistula the risk of hemodynamically relevant stenoses is increased. Establishment of new ultrasound methods like B-flow and advanced dynamic flow (ADF) enable direct visualization of the flow in the area of the anastomosis. In addition, high-resolution ultrasound techniques allow improved flow detection without aliasing. Our report addresses the topics of examination strategy, possible complications, and treatment like percutaneous intervention techniques.