Abstract. In this paper a two-dimensional simulation of organic light emitting devices (OLEDs) using an adaptive computing technique is presented. A set of drift-diffusion equations including models of interface traps is solved numerically to explore the transport property of OLED structures. The adaptive simulation technique is mainly based on the Gummel's decoupling algorithm, a finite volume approximation, a monotone iterative method, a posteriori error estimation, and an unstructured meshing scheme. With this computational approach, we investigate the intrinsic and terminal voltage-current characteristics of OLEDs with respect to different material parameters, thickness of materials, and length of structure.