The polydioxythiophenes PEDOT and more recently ProDOT have emerged as champion materials in the field of organic bioelectronics, both in the domain of biosensing and also for integration with living cells (both in vitro and in vivo). Although polydioxythiophenes in their pristine forms have shown great promise for bioelectronics, in order to broaden the spectrum of applications, a biofunctionalization step is essential. In this review we summarise the methods that have been used thus far to biofunctionalize polydioxythiophenes in an effort to improve the biotic/abiotic interface. We provide an introduction to this class of materials, focusing particularly on the different methods of synthesis (chemical oxidative polymerization, vapor phase polymerization or direct electrochemical polymerization) and discuss the implications of synthesis on biofunctionalization. Rather than provide an exhaustive review, we chose to highlight key examples of biofunctionalization techniques for polydioxythiophenes for specific biomedical applications. Finally, we conclude with a brief discussion of the importance of biofunctionalization methods in future bioelectronics applications, and some ideas for future directions in this field. Figure 1: Structures of polydioxythiophene monomers and dopants. a) structure of EDOT monomer and modified EDOT with different pendant groups (carboxyl shown). b) structure of ProDOT monomer and modified ProDOT with different pendant groups (ProDOT-ene shown) c) Usual dopants such as polystyrene sulfonate (PSS) polymer, tosylate (TOS) monomer, and perchlorate monomer CPs came to the forefront in 1976 with research done by Alan MacDiarmid, Hideki Shirakawa and Alan Heeger, and have since been shown to display many desirable characteristics for a variety of applications. 3,4 An important example is their mixed conductivity; In CPs, electrons move primarily along the conjugated backbone of the polymer, but charge hopping between chains also occurs. CPs typically have an open microstructure that allows for facile ionic transport. This mixed (electronic and ionic) conductivity has been shown to be very useful for certain biomedical applications. 5 The most frequently used CPs for biomedical applications include polypyrrole, polyaniline and polythiophenes. 6 Although polypyrrole lead