Objective To investigate the effectiveness of autologous bone marrow mononuclear cells transplantation on lower l imb chronic venous ulcer. Methods Between May 2009 and September 2010, 17 patients with lower l imb chronic venous ulcer were treated with autologous bone marrow mononuclear cells transplantation (transplantation group) and 10patients treated without cells transplantation served as control group. In the transplantation group, there were 9 males and 8 females with age of (33.3 ± 6.1) years, including 11 cases of simple great saphenous vein varicosity and 6 cases of chronic venous insufficiency; the area of ulcer was (4.39 ± 2.46) cm2; and the duration of ulcer ranged from 3 months to 6 years. In the control group, there were 4 males and 6 females with age of (39.2 ± 10.3) years, including 7 cases of simple great saphenous vein varicosity and 3 cases of chronic venous insufficiency; and the area of ulcer was (5.51 ± 2.63) cm2; and the duration of ulcer ranged from 3 months to 2 years. All patients in both groups were classified as C6 according to Cl inical Etiology Anatomy Pathophysiology (CEAP) classification. No signficant difference was found in the general data between 2 groups (P gt; 0.05). The heal ing process of ulcer was observed. The granulation tissue was harvested for HE staining before operation and at 3 days after operation in the transplantation group. The microvessel density (MVD) and vascular endothel ial growth factor (VEGF) expression of ulcer granulation tissue were observed. Results In the transplantation group, ulcer heal ing was accelerated; complete heal ing was observed in 15 cases, partial heal ing in 1 case, and no heal ing in 1 case with the median heal ing time of 22 days. However, in the control group, the heal ing process was slower; complete heal ing of ulcer was observed in 7 cases and no heal ing in 3 cases with the median heal ing time of 57.5 days. There was significant difference in the heal ing time between 2 groups (Z=0.001 4, P=0.002 7). HE staining showed a great number of microvessels in the granulation tissue in the transplantation group. The immunohistochemical staining showed that MVD was significantly increased (t=3.120, P=0.008) after cell ransplantation (32.1 ± 12.8) when compared with that before transplantation (22.1 ± 6.7). The VEGF expressionafter transplantation (8.05% ± 5.10%) was increased sl ightly when compared with that before transplantation (6.13% ±4.20%), but the difference was not significant (t=1.150, P=0.268). Conclusion Autologous bone marrow mononuclear cellstransplantation can stimulate granulation tissue growth and improve ulcer heal ing.