This study aimed to compare the effects of action potential simulation with vibration in reducing neck and shoulder pain and disability in subjects with trapezius and levator scapula muscles trigger points. This randomized controlled trial was performed in Zahedan University of Medical Sciences, in 2009. Thirty patients with trigger points in upper trapezius and levator scapula were recruited through simple non probability sampling. Patients were selected based on following inclusion criteria: Participants aged between 18 till 25 years old, patients diagnosed with trigger point in trapezius and levator scapula muscles, patients who have been muscle pain without neurological sign as chief complaint, no history of respiratory diseases, surgery, and neck & thoracic spine structural disorders. Patients were excluded if they had insufficient treatment, using other therapeutic modalities during the study, trauma, and doing surgery during the study. Patients were randomly assigned to either a vibration group (N=15) or an action potential simulation group (N=15). Before and after treatment, we assessed neck disability with Neck Disability Index, neck pain with Visual Analogue Scale, shoulder pain and disability with Shoulder Pain and Disability Index and cervical range of motion with specific neck goniometer. In vibration group, we used vibrator with moderate pressure and low frequency, 2500 cycle per minute and for 30 minutes per session. In action potential simulation group, action potential simulation was applied with intensity of 1mA, 150 Hz frequency, for 16 minutes per session.