Biosensors are, by definition, sensing devices comprising a biological component (enzyme, antibody, animal or plant cell, oligonucleotide, lipid, microorganisms, etc.) intimately connected to a physical transducer (electrode, optical fiber, vibrating quartz, etc.). This dual configuration permits a quantitative study of the interaction between a drug compound and an immobilized biocomponent. Ideally, biosensors should be readily implemented and allow for low reagent and energy consumption. Enzyme‐based biosensors can be applied in the pharmaceutical industry for monitoring chemical parameters in the production process (in bioreactors). Affinity biosensors are suitable for high‐throughput screening of bioprocess‐produced antibodies and for candidate drug screening. They are suitable for selective and sensitive immunoassays in clinical laboratories and for decentralized detection of drug residues. Enzyme‐based biosensors may be used in hospitals for bedside drug testing, emergency control, in patient treatment control (anticancer therapy) etc. Current research efforts are focused on proteins, tissues, or living cells immobilized in microfabricated configurations for high‐throughput drug screening and discovery. Such devices can comprise several different microelectronic sensors and biosensors sensitive, for example, to pH, temperature, impedance, dissolved oxygen, etc. for a multiparametric monitoring. Of equal new interest are the oligonucleotide‐immobilized biosensors for interactions studies between a surface linked DNA and the target drug or for hybridisation studies. This short review summarizes several recent trends dedicated to the development and application of biosensors in the pharmaceutical arena.