In this chapter we will discuss about femoral nerve block and popliteal sciatic nerve block under ultrasound guidance. The femoral nerve (L2-L4) runs down the posterolateral wall of the pelvis behind the fascia iliaca. The femoral artery and vein lie anterior to the fascia iliaca. Ultrasound application helps to monitor the spread of local anesthetic and needle placement and make appropriate adjustments, should the initial spread be deemed inadequate. The main structures to visualize for femoral nerve block are femoral artery, femoral vein, and fascia iliaca. The femoral artery should be located first using color Doppler and pulse wave Doppler. The sciatic nerve is the larget nerve supplying the leg. It is formed by the fusion of Lumbar fourth, fifth nerves and 3 sacral spinal nerves. There are two approaches for popliteal sciatic block, lateral approach and posterior approach. In both position ultrasound image remains same but the patient position differs.