Several three-terminal organic bioelectronic structures have been proposed so far to address the needs for a variety of biosensing applications. The most popular structures utilize organic field-effect transistors operated in an electrolyte, to detect both proteins and genomic analytes. They are endowed with selectivity by immobilizing a layer of bio-recognition elements. These features along with the foreseen low-cost for their production, make them very appealing for point-of-care biomedical applications. Electrolyte-gated organic field-effect transistors (EGOFETs) and organic electrochemical transistors (OECTs) are prominent for detecting biochemical recognition events, as they are easily fabricated and operated. This Special Issue is dedicated to advanced and emerging concepts and technologies of transistor amplified detection for different biochemical reactions. Topics include field-effect transistor (FET)–based transduction of biochemical events, such as ionic and enzymatic, as well as immunometric or genomic interactions. Innovative approaches concerning large-area processable semiconductors (SCs) as channel materials are also of interest, as well as biocompatible organic semiconductors and so amenable to be used for implantable bioelectronic systems. Research papers, short communications, and reviews are all welcome. If the author is interested in submitting a review, it would be helpful to discuss this with the guest editor before submission.