The detection of pathogenic bacteria is the key in prevention and identification of problems related to health and safety. Biosensors are analytical devices that allow the detection of biomolecules in a label-free, real-time, specific, highly sensitive format and can essentially serve as low-cost and highly efficient devices for diagnosis of pathogenic diseases. Different types of biosensor are being employed for detection of pathogenic microbes. Biosensors attach biological materials to a physiochemical transducer. The transducer is a device that produces the optical, calorimetric, acoustic, electrochemical, or magnetic signal of interaction between specific interaction partners such as target analyte and the immobilized biological materials. Immobilized layer produces a physicochemical change that is detected by the transducer. The transducer then yields a digital electronic signal proportional to the concentration of a specific analyte. Different types of biosensor are being employed for detection of pathogenic microbes. Diagnosis of pathogens by biosensors may become more popular than the standard methods, although achieving high-throughput and sensitivity are still important challenges.