Introduction Traumatic brain injury (TBI) causes long-term neurological disability in 7% of survivors for which there is no clinically proven therapies. Transcranial direct current stimulation (tDCS) is a prospective treatment currently being clinically tested in TBI patients. However, due to a lack of animal studies, the mechanisms and optimal stimulation parameters for tDCS are unknown. Objectives Our objective is to evaluate mechanisms and the efficacy of tDCS in a mouse model of TBI. We hypothesized that tDCS, applied during recovery phase after TBI, improves long-term neurologic outcome involving a sustained increase in cerebral blood flow (CBF). Materials & methods TBI was induced by controlled cortical impact (CCI) with a Benchmark Controlled Cortical Stereotaxic Impactor using a 3-mm flat-tip impounder deployed at a velocity of 5 m/s and a depth of 2.0 mm from the cortical surface. Pre-trained mice were subjected to TBI and tested at 3 weeks after trauma by Rotarod for neurologic motor deficits. Anodal tDCS (0.1 mA/15 min) or sham stimulation were applied every day for 4 days, starting 2 weeks after TBI. Using in vivo 2-photon laser scanning microscopy over the parietal cortex we monitored changes in microvascular blood flow and tissue oxygenation (NADH) before and after tDCS treatment. Results Anodal tDCS improved motor function in mice after TBI compared to sham treated mice as shown by latency to fall from the rotating rod (75.4 ± 12 s. vs. 55.6 ± 16 s, n = 4, P Conclusions tDCS acutely increases brain microvascular flow and tissue oxygenation that could contribute to neurologic improvement after TBI. The vasodilation observed may be mediated by tDCS-stimulated nitric oxide release. Support NIH-NIGMS P20GM109089-01A1, Rio Grande Neurosciences.