Bone-marrow-derived mesenchymal stem cells (BM-MSCs) were found to markedly increase atherosclerotic lesion size. The aim of this paper was to investigate whether BM-MSCs contribute to vascular remodeling and calcification after balloon injury in hyperlipidemic rats. Labeled BM-MSCs were found in the lesion of hyperlipidemic rats after balloon injury. Comparing injury group, transferred BM-MSCs significantly triggered vascular negative remodeling, characterized by the changes of remodeling index (0.628 ± 0.0293 versus 0.544 ± 0.0217), neointimal area (0.078 ± 0.015 mm(2) versus 0.098 ± 0.019 mm(2)), PCNA index (23.91 ± 6.59% versus 43.11 ± 5.31%), and percentage of stenosis (18.20 ± 1.09% versus 30.58 ± 1.21%). Apparent vascular calcification was detected in medial layers at 6 weeks after balloon angioplasty, which may be associated with upregulation of bone morphogenetic protein-2 (BMP-2). Our data indicated that unselected BM-MSCs transfer may induce vascular remodeling and calcification after balloon injury in hyperlipidemic rats.