This paper reviews fundamentals and applications of modulated induction thermal plasmas that have been developed. The coil-current modulation of the order of several hundreds amperes allows one to make a large disturbance in high-pressure and high temperature plasmas, and also to control the temperature and radical density in thermal plasmas in time domain. Examples will be introduced on application of the modulated induction thermal plasma to surface modification, in which thermally and chemically nonequilibrium effects are essential in temperature and radical density fields. Finally, dynamic behaviors of an arbitrary-waveform modulated induction thermal plasma that has recently been developed were also introduced as a new type of modulated induction thermal plasmas. © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.