Background: Cervical myofascial pain syndrome (MPS) is a common clinical complaint in the daily practice of musculoskeletal physicians. Its prevalence of 21% in the general population. MPS is the major reason of chronic regional pain, such as pain of shoulder, back and facial pain Objective: To identify neuropathy of the spinal accessory nerve in MPS patients clinically and by integrated nerve conduction and neuromuscular ultrasound studies. Methodology: This cross sectional study enrolled 60 cases with unilateral chronic MPS, all cases were investigated for history, underwent clinical checkup (general and local), assessment of the pain intensity by numerical rating scale (NRS), Nerve Conduction Study (NCS) and ultrasonographic measurement of the cross sectional area (CSA) of the Spinal Accessory Nerve (SAN) in both symptomatic and asymptomatic healthy side for comparison. Results: NCS revealed presence of SAN neuropathy in 23.3% of MPS side. All of them (100%) showed demyelinating lesion, while 4 patients (28.5%) showed mixed type of neuropathy. There was highly considerable higher mean of distal latency on the affected side which was 3.46±1.27 ms compared to the healthy side which was 2.77±0.99 ms, (p<0.001). Also, a highly significant lower mean of motor amplitude on the affected side which was 6.34±2.14 mv, compared to the healthy side which was 7.31±2.38 mv, (p<0.001).  As for ultrasonographic assessment, the mean of CSA of the SAN on the affected side was 7.30±1.51 mm² compared to the healthy side which was 4.67±0.96 mm², with highly statistically significant difference, (p<0.001). Conclusion: Spinal accessory neuropathy is significantly increased in MPS patients, NCS and neuromuscular ultrasonography could lead to more reliable diagnosis.