During the last two decades, organic electroactive materials have been explored as the working material in a vast array of electronic devices, promising low-cost, flexible, and easily manufactured systems. The same materials also possess features that make them unique in bioelectronics applications, where electronic signals are translated into biosignals and vice versa. Here we review, in the broadest sense, the field of organic bioelectronics, describing the electronic properties and mechanisms of the organic electronic materials that are utilized in specific biological experiments.