We present the characterization of an anthracene single-crystal organic field-effect transistor in the temperature-range of 4.2 to 290 K We recorded the source-drain current as a function of the applied voltages (source-drain and gate). The measured curves exhibit a superlinear dependence when plotted on a log-log scale with an exponent larger than two, which is typical of a trap-filling regime. At low temperatures, the source-drain current becomes temperature independent and shows a plateau. We estimate a lower bound of the mobility at different temperatures.