200 patients with shoulder musculoskeletal pain were randomly assigned to either experimental Group I (n=100), which received interferential laser, or control Group II (n=100), which received conventional laser therapy. A laser was applied in contact mode through ten sessions, on 5 shoulder points (7 Joules/point) per session. Outcomes from Visual Analogue Scale (VAS) score and Shoulder Pain Disability index (SPADI), recorded before and after laser treatment, showed no significant difference between the two laser treatments and demonstrated that interferential laser treatment was equally safe.