Co-culture of bone forming cells and endothelial cells to induce pre-vascularization is one of the strategies used to solve the insufficient vascularization problem in bone tissue engineering attempts. In the study, primary cells isolated from 2 different tissues of the same animal, rat bone marrow stem cells (RBMSCs) and rat aortic endothelial cells (RAECs) were co-cultured to study the effects of co-culturing on both osteogenesis and angiogenesis. The formation of tube like structure in 2D culture was observed for the first time in the literature by the co-culture of primary cells from the same animal and also osteogenesis and angiogenesis were investigated at the same time by using this co-culture system. Co-cultured cells mineralized and formed microvasculature beginning from 14 days of incubation. After 28 days of incubation in the osteogenic medium, expression of osteogenic genes in co-cultures was significantly upregulated compared to RBMSCs cultured alone. These results suggest that the co-culture of endothelial cells with mesenchymal stem cells induces both osteogenesis and angiogenesis. (C) 2016 Elsevier Inc. All rights reserved.