In this work, an evolutionary parameter extraction procedure is combined with a compact model for the current-voltage characteristics of organic thin-film transistors as a part of a circuit design tool to extract the device parameters. This procedure can be used to overcome shortcomings of previous parameter extraction procedures. The proposed evolutionary procedure can be used in those situations whereby the parameter set extracted by other procedures does not comply its physical meaning, or if a poor agreement between the experimental data and the analytical results exists. In the last case, the evolutionary procedure can be used as a problem optimization method. After the evolutionary parameter extraction procedure is applied to the transistor output characteristics, the obtained results show an excellent agreement with the experimental data.