PURPOSE:To investigate by histomorphometry the distraction osteogenesis by Ilizarov technique in dog radius with the use of autologous stem cells in regenerated bone. METHODS:Ten dogs (20 radiuses) underwent the osteotomy of 20% of extension of their radiuses, and osteogenic distraction using the Ilizarov technique after this procedure at rate of 1mm per day divided into 0.5mm every 12 hours. The elongation was performed until the regeneration reached 20% of the total length of the radius. The stem cells were isolated, concentrated and injected in the regenerated bone, when it reached 10% of the length of the entire radius. The regenerated bone was evaluated using histomorphometric analysis when the elongation was 20% the size of radius. RESULTS: The bone formation was evidenced by histomorphometric indices were significantly greater in the study group. In the histology evaluation the type of healing was mixed in 80% (intra membrane and endocondral) in both groups; the osteoblastic activity from moderate to intense was greater in the study group; and the space occupied by the newly-formed bone tissue was more evident in the study group. CONCLUSIONS:The histomorphometric indices in this study expressing the microarchitecture, trabecular thickness, trabecular spacing, number of trabecula and quantity of bone that was significant in the group study. These data suggest that the use of undifferentiated stem cells autologous bone marrow in the regenerate bone induces osteogenesis and bone quality.