Tumor necrosis factor-alpha (TNF-α) is elevated early in injured brain after traumatic brain injury (TBI), in humans and in animals. However, it is not known whether etanercept (a TNF-α antagonist) improves outcomes of TBI by attenuating microglia-associated, astrocytes-associated, and/or neurons-associated TNF-α expression in ischemic brain. A well clinically relevant rat model, where a lateral fluid percussion is combined with systemic administration of etanercept (50mg/kg, i.p.) after TBI, was used. To examine the neuronal and glial production of TNF-α, we performed Immunofluorescence staining to identify neurons-TNF-α, astrocytes-TNF-α, and microglia-TNF-α double positive cells in the injured brain of the cortex, white matter, hippocampus, and hypothalamus in TBI animals treated with or without etanercept. The rats were anesthetized with sodium pentobarbital (25 mg/kg, i.p.) and a mixture containing ketamine (4.4 mg/ kg, i.m.), atropine (0.02633 mg/kg,i.m.), and xylazine (6.77 mg/kg, i.m.), and received a 4.8-mm craniotomy to anchor the modified plastic syringe hub over the exposed dura of the right parietal cortex. A moderate FPI (2.2 atm) was produced by rapidly injecting a small volume of saline into the closed cranial cavity with a fluid percussion device (VCU Biochemical Engineering, Richmond, VA, USA). Behavior on an inclined plane was used to assess changes in limb strength. In addition to inducing brain contusion as well as motor deficits, TBI caused significantly higher numbers of microglia-TNF-α double positive cells, but not neurons-TNF-α or astrocytes-TNF-α double positive cells in the injured brain areas than did the sham operated controls, when evaluated 3 days after TBI. The TBI-induced cerebral contusion, motor deficits, and increased numbers of microglia-TNF-α double positive cells in the injured brain were all significantly attenuated by etanercept therapy. Early microglia overproduction of TNF-α in the injured brain region after TBI contributes to cerebral contusion and motor deficits, which can be attenuated by etanercept therapy.