ABSTRACf. The poly(3-alkylthiophenes) represent a new generation of conducting polymers, that exhibit both solution and melt processability. These properties open new possibilities for the utilization of conducting polymers in practical applications. Furtheonore, the solubility of these polymers enables the characterization of the physical and chemical structure in greater detail than hitherto have been possible. In this chapter we give a brief review of the synthetic routes to the poly(3-alkylthiophenes) as well as an overview of some of the recent results on the physical and chemical characterization of this class of materials. In this overview we include results on stability properties, transport properties, thermo-and solvatochromism. We also discuss some aspects of the utilization of the poly(3-alkylthiophenes) in applications.