Ionizing radiation is known to generate reactive oxygen species (ROS) that can be removed by antioxidants. L-carnitine, a natural component of mammalian tissue, is a necessary factor in the utilization of long-chain fatty acids to produce energy. Furthermore it has been shown that L-carnitine is an antioxidant which has a scavenger effect on ROS and a stabilizing effect on damaged cell membranes. The aim of the study was to evaluate the potential protective effect of L-carnitine on radiation-induced free radicals in hamsters. L-carnitine was given by gavage at a dose of 50 mg/kg for 15 consecutive days before irradiation with a single dose of 8 Gy. 24 h after radiation exposure, the hamsters were sacrificed and samples were taken from blood and tissues, and the biochemical and histopatological determinations were carried out. In the irradiated group, there were significant increases in plasma and liver malondialdehyde (MDA) with marked reduction in glutathione (GSH) levels in the liver, compared with controls. In red blood cells, superoxide dismutase (SOD) and catalase activities were also reduced. All these effects were reversed by L-carnitine. In conclusion, L-carnitine with its antioxidant and free radical scavenging properties could play a modulatory role against the cellular damage produced by free radicals induced by ionizing radiation.