The purpose of this study was to compare the effects of diclofenac phonophoresis with ergonomic instructions on reducing neck and shoulder pain and disability in women with myofascial trigger points in trapezius muscle. This randomized controlled trial was performed in Zahedan University of Medical Sciences, in 2009. Thirty patients with trigger points in trapezius muscle were participated through simple non probability sampling. Patients were selected based on following inclusion criteria: Age between 18-25, having trigger point in trapezius muscles with main complaint: muscle pain without neurological sign, 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 study, trauma and surgery during the study. Patients were randomly assigned to one of three equal groups: diclofenac phonophoresis, ergonomic instructions, and control groups. In phonophoresis group, frequency of ultrasound 1 MHz, continuous mode, intensity 1.5 W/cm2 and duration 4.5 min was used. Ergonomic group received instructions in order to maintain appropriate posture during activity of daily livings. Control group received ultrasound without output. A 12 session treatment program, during 4 weeks, 3 sessions per week was performed. Before and after intervention, we assessed neck pain with Northwick Park Neck Pain Questionnaire and shoulder pain and disability with Shoulder Pain and Disability Index.