Mesenchymal stem cells (MSCs) have a great potential in the field of tissue engineering and regenerative medicine on account of their ability to self-renew and differentiate into various lineages. MSCs could be differentiated by a number of ways. Electric field is known to bring about differentiation, migration, proliferation, and reorientation of MSCs. Hence, we aim to create a bioreactor to attain osteodifferentiation of human-derived MSCs in the presence of osteoinduction medium (OIM) in combination with or without alternating current (AC) fields. A stimulation bioreactor was specially designed for the exposure of adipose-derived stem cells (ASCs) to an electric field of 20 mV/cm, 60 kHz. The electric field potential (E) within the chamber was simulated using COMSOL. The morphology, proliferation, and osteogenic differentiation of ASCs under the influence of electrical stimulation were studied. By week three, electrically stimulated ASCs exhibited their typical spindle-shaped morphology. Stimulated ASCs were more intensely stained with alkaline phosphatase and alizarin red, the markers of osteogenic differentiation, as compared to the unstimulated control groups. Darker stained regions correlated with the COMSOL simulation which showed constant electric potential at the same place. The results depicted a clear difference between the effect of constant and varying electric potential on osteodifferentiation of ASCs. Picogreen assay revealed lower DNA contents of electrically stimulated ASCs compared to the control group. In this study, we have additively enhanced the osteodifferentiation potential of ASCs by electrical stimulation and have proved that it is constant electric field potential which specifically augments osteogenic differentiation. We have successfully developed a bioreactor to improve the osteodifferentiation of ASCs by an electrical field, which could be applied in regenerative therapy strategies of bone fracture treatment. © 2018, Taiwanese Society of Biomedical Engineering.