Carrier transports, especially the mobilities in organic materials that are interested for a variety of functional optoelectronics devices are reviewed. Several factors that determine the mobilities are discussed taking into consideration the molecular structure, arrangements and spaces between molecules as well as impurities. As the example, the mobilities of conducting polymers, poly(3-alkylthiophene) films measured by means of time-of-flight method and field effect are discussed as functions of various alkyl chain length and the regioregularity.