A handheld device workout coach system includes: at least a handheld device installed therein with a coaching program and having a near field communication (NFC) module and a ID recognition data; at least a fitness device having a master control unit, a near field communication (NFC) module corresponding in position and function to the master control unit, and a platform; and a server stored therein with workout prescriptions downloadable by the at least a handheld device and available to the coaching program. The master control unit has an equipment recognition data. The handheld device and the fitness device get connected by near field communication (NFC) technology as soon as the handheld device is positioned on the platform of the fitness device and recognize each other to thereby execute the coaching program instantly and automatically, such that a corresponding one of the workout prescriptions instructs a user to take exercise.