Following traumatic brain injury, there is an enhanced cell proliferative and neurogenic response in the young adult hippocampus, which may be associated with innate cognitive recovery. However, in the aged brain, an increased level of inflammatory cell responses was observed following injury concomitant to decreased hippocampal neurogenesis and cognitive recovery in the aging population. This suggests that excessive inflammation produced in the injured aging brain has a detrimental effect on neurogenesis and cognitive function. In this study, we examined the effect of anti-inflammatory treatment with minocycline on cell proliferation and generation of new neurons in the dentate gyrus (DG) of the hippocampus in both young and aged rats. Fisher 344 rats aged at 3 months and 20 months were subjected to a moderate lateral fluid percussion injury (LFPI) or cortical impact injury (CCI). Minocycline was administered intraperitoneally starting either at 30 minutes or 4 hours post-injury, thereafter twice daily for 2 days. BrdU was injected at 2 days post-injury to label injury-induced proliferating cells. To examine the effect of minocycline on cell proliferation, generation of new neurons, and inflammatory cell response at the acute stage post-injury, the rats were perfused 3 days post-injury. Brain sections were immunostained for BrdU and early neuronal marker doublecortin (DCX). The results show that short-term anti-inflammatory treatment with minocycline reduces the cell proliferative response, presumably inflammatory cell responses, in young and aged rats following LFPI and CCI injury, and enhances generation of new neurons in the hippocampus in both young and aged rats following LFPI and in aged rats following CCI injury. Therapies that enhance hippocampal neurogenesis may also have potential to improve cognitive recovery following TBI.