The cervical plexus (CP) block is a commonly used technique for providing analgesia and anesthesia during medical procedures in the head and neck region. The block can be classified into superficial, intermediate, and deep categories. The ultrasound technique is preferred for performing the CP block, as it is considered safer and more accurate. This chapter provides an overview of the anatomy of the cervical plexus, indications for the blocks, and ultrasound-guided techniques. The potential complications associated with the CP block and their management are also discussed. The cervical plexus is formed by the ventral rami of the first four spinal nerves (C1–C4) and has two branches: the muscular and cutaneous branches. The muscular branch includes the phrenic nerve and the Ansa cervicalis, while the cutaneous branch provides sensory innervation to the skin of the neck. The cervical plexus is located beneath the sternocleidomastoid muscle and passes through the cervical fascia at the Erb point. During the CP block, the patient is typically positioned in a supine, semi-sitting position with the head slightly contralateral. Alternatively, the lateral decubitus position may be used. The patient’s comfort and any limitations should be considered when selecting the appropriate position. In obese patients, visualization of the posterior border of the sternocleidomastoid muscle may be difficult, and the patient may be asked to lift their head off the bed to facilitate palpation of this area. The high-frequency linear probe (13–18 MHz transducer) is used for an in-plane approach, and it is placed over the midpoint of the posterior border of the sternocleidomastoid muscle. The CP block is commonly used for carotid endarterectomy, as well as for surgeries involving the head, neck, shoulder, and upper chest region. The superficial block is a safe, superficial, and easy-to-perform block. The intermediate block is applied between the investing deep fascia and the prevertebral fascia at the posterior cervical space, and the needle should be outside the carotid sheath to avoid complications. The deep block is performed under the prevertebral fascia by targeting the nerve roots, and careful consideration should be given to the potential complications, such as phrenic nerve palsy and fatal airway obstruction.