In order to study the effects of infrared laser irradiation on biological systems, the levels of copper and zinc in various irradiated tissues have been investigated. The zinc level in the muscle of the irradiated group increased (P<0.001) compared with the control group while in submandibular glands its level decreased (P<0.001). The copper levels in these two types of tissues decreased significantly (P<0.001). In irradiated skin, both copper and zinc levels increased compared with the control group (P<0.005). Quantitative determination of the trace elements copper and zinc indicated the necessity for more detailed studies of the effect of infrared irradiation at the cellular level.