In this paper, an enhanced model for organic transistors is presented. It is generally applicable to organic transistors using polymer semiconductors and small molecules, respectively. Furthermore, this enhanced model can be used for p-type, n-type and ambipolar organic transistors. It will be compared to two agent of organic transistor models. On the basis of the output characteristic of a p-type organic transistor based on pentacene as active layer the advantages and the disadvantages of each model are pointed out.