LP-BM5 retrovirus infection and hormone synthesis modulate many physiological systems that could affect physical activity. Infection induced oxidative damage and immunodeficiency of female mice which hormone supplement prevented. Therefore, the effects of retrovirus infection and hormone supplementation were assessed on physical activity using a computerized video system. Retroviral infection increased activity when stationary while lowering average speed and resting time. Hormone supplementation partially modified changes due to murine AIDS. Dehydroepiandrosterone (DHEA) or melatonin (MLT) supplementation restored the average speed; ambulatory time and distance traveled of retrovirus infected mice. MLT as well as the combination of DHEA + MLT increased body movement, but decreased average speed and distance traveled. Thus, retrovirus infection had significant effects on physical activity. Further studies into the relationship between the DHEA and/or MLT and physical activity will assert the contribution of these hormones to the treatment of murine AIDS.