Disclosed are a light emitting device having a plurality of light emitting cells connected in series and a method of fabricating the same. The light emitting device includes a buffer layer formed on a substrate. A plurality of rod-shaped light emitting cells are located on the buffer layer to be spaced apart from one another. Each of the light emitting cells has an n-layer, an active layer and a p-layer. Meanwhile, wires connect the spaced light emitting cells in series or parallel. Accordingly, arrays of the light emitting cells connected in series are connected to be driven by currents flowing in opposite directions. Thus, there is provided a light emitting device that can be directly driven by an AC power source.