Aim To investigate the effect of losartan on neointimal proliferation and expression of nuclear factor κB(NF κB). Methods Japanese White rabbits underwent abdominal aorta balloon de endothelialization and then were treated with a 1.5% cholesterol diet for 8 weeks. Then balloon angioplasty was performed on the injured arteries. Immediately after balloon angioplasty, the rabbits of the losartan group was orally administered with losartan [10 mg/(kg·d)], while the rabbits of the control group were given normal saline. Animals were killed four weeks after angioplasty, and excised artery segments were prepared for histomorphological observation and α smooth muscle actin, macrophage, NF κB and intracellular adhesive molecule 1 (ICAM 1) were investigated by immunohistochemistry analysis. Results Losartan treatment significantly inhibited neointimal proliferation. Compared with the control group, the intimal thickness (IT), intimal area (IA), the ratio of IT/MT and IA/MA of the losartan group were significantly reduced (p<0.01). Also, macrophages and smooth muscle cells (SMC) in the neointima were significantly diminished (p<0.01 and p<0.05) and the expression of NF κB and ICAM 1 were respectively decreased in the losartan group (p<0.01 and p<0.05). Conclusions These findings suggest that losartan could significantly relieve neointimal proliferation after balloon angioplasty, possibly through inhibiting angiotensinⅡ and NF κB, thus inhibits inflammatory reaction, migration and proliferation of SMC as well as formation of neointima which contributes to restenosis after balloon angioplasty.