Water and food-borne diseases are public health problems. It is estimated that only water-borne diseases cause 2.2 million deaths annually. E. coli is one of the most important bacteria in water monitoring and is on the WHO's list of priority pathogens for diagnosis and treatment. Conventional methods for detecting E. coli are not effective due to their time-consuming nature, the need for expensive equipment, and low sensitivity. Therefore, a rapid diagnostic method is essential for accurate detection of E. coli. Here, a Field-effect Transistor (FET) was used to detect E. coli based on rGO, AuNPs, and ssDNA-aptamer. After characterizing the rGO-AuNPs-Apt FET, the current of the nanobiosensor was measured with each modification. The nanobiosensor's linear range was (3-3 × 10