An apparatus for monitoring a conscious subject, such as a rat or human, in a strong magnetic field, such as that generated by a magnetic resonance imaging (MRI) scanner, includes sensors and wireless transmitter. The sensors detect physiological parameters of the subject, and the transmitter sends a wireless signal representing the parameters. A system for monitoring a conscious subject in a magnetic field includes a wireless monitor, wireless interface, and computer. The wireless monitor includes the sensors, filters, microcontroller, and wireless transmitter. The wireless interface receives the signal from the wireless monitor and transmits a corresponding signal to the computer. A method of monitoring a conscious subject in a strong magnetic field includes disposing the sensor in the magnetic field, sensing a physiological parameter from the subject, providing a sensed signal representing the parameter, disposing a wireless transmitter on the subject, and transmitting a signal representing the sensed parameter.