Herpes zoster presents clinically with cutaneous vesicular eruption and pain along the dermatome, but it can sometimes cause muscular paralysis. When the disease involves cervical root, it is included in the differential diagnosis of shoulder diseases. A sixty-six year old patient, complaining of severe pain and weakness of his left shoulder, was referred to the authors as having a partial tear of the supraspinatus tendon on MRI. However, the authors found out a paralysis of the sixth cervical root in the patient by electrophysiologic studies, noting that the patient had been affected with a herpes eruption in the neck and arm two months before. Zoster paresis has been reported to be associated with the cutaneous eruption within two weeks of its onset, making its diagnosis not so difficult. The authors report a case of delayed-onset muscular paralysis after cutaneous herpes zoster, which presented just like a rotator cuff tear.