Objective: To investigate the effect of adenoviral vector-mediated AT2R gene transfection on neointimal hyperplasia after rat carotid artery balloon injury. Methods: AT2R gene was transferred into rat carotid arteries by recombinant adenovirus pAd-AT2R after the establishment of rat carotid balloon injury restenosis model. The arteries were harvested on the 14th day after gene transfer. The efficiency of trans gene delivery was measured by the expression of adenovirus-encoding green fluorescent protein (GFP) under fluorescent microscope. The expression of AT2R and PCNA (proliferating cell nuclear antigen) was evaluated by RT-PCR, immunocytochemistry, immunofluorescence staining, confocal microscopy, respectively. The ratio of intimal to medial area (I/M) was quantified with images and determined by an image analysis system. Results: GFP-positive area in adventitia, media and the forming neointima was about 400％. Adenoviral delivery of rat AT2R gene up-regulated AT2R expression in balloon-injured rat carotid and reduced PCNA expression and I/M significantly in neointima (P＜0.01). Double immunofluorescence labeling of AT2R and PCNA also showed that AT2R gene transfer inhibited VSMCs proliferation in neointima. Conclusion: AT2R gene transfer may be a novel promising therapy to limit neointimal hyperplasia.