Lifestyle factors exert a significant influence on the structure and function of the brain. These effects are particularly pronounced in the hippocampus, crucial for learning and memory, known for its plasticity and the existence of adult neurogenesis—the generation of new neurons in adulthood. While the enhancing effect of environmental stimulation on adult neurogenesis has been extensively studied, there has been a notable lack of attention to its impact on other cell types within the adult neurogenic niche, such as microglia.In this study, we investigated the effects of environmental stimulation on hippocampal microglia by housing two-month-old mice in an enriched environment (EE) featuring various stimuli, including tubes, shelters, and a running wheel, for six weeks; or in standard cages. As expected, EE resulted in increased adult neurogenesis. However, intriguingly, we observed a reduction in the area occupied by microglia in the hippocampus following EE, despite no change in their overall number. Our analysis suggested that microglia play an active role in monitoring newly generated cells, as indicated by a higher rate of colocalization than would be expected by chance alone. Most significantly, EE was found to diminish microglial surveillance of young neurons.Our findings demonstrate that EE influences the interaction between newborn neurons and microglia, highlighting the need for further investigation into the role of microglia in mediating the effects of environmental stimulation on neurogenesis.Funding: Science and Innovation Spanish Ministry: PID2022-140525NB-I00 y PID2022-140456NB-I00. POCTEP: Cross-3DTool-4ALS (Programa Interreg VI-AEspaña-Portugal (POCTEP) 2021-2027), and Erasmus+ programme Partnership for Cooperation (2023-1-PL01-KA220-HED-000160284).