A replaceable alcohol sensor module for use with a breathalyzer. The alcohol sensor module requiring calibration can be removed from the body of the breathalyzer and replaced with a new alcohol sensor module. The alcohol sensor module has at least an alcohol sensor and a circuitry mounted on a PCB that removable connects the replaceable alcohol sensor module to the breathalyzer. The circuitry transmits the signal and/or electrical current generated by the alcohol sensor to a processing unit of the breathalyzer for processing.