Abstract: The silent alarm comprises a wrist band housing which can be attached to the wrist of a person. A signal receiving device is mounted in the wrist band housing for receiving a signal from a clock controlled transmitter. Vibratory means are also mounted in the housing and are connected to the signal receiving device. A battery is mounted in the wrist band to energize the vibratory means when the signal receiving device receives a signal in order to quietly awaken a sleeping person wearing the wrist band.