Abstract: The stabilization of austenite during isothermal holding above Ms has been investigated using 1%-carbon, 5%-nickel steel. The stabilization increases with the amount of martensite present, but it is established that the martensite is not an important factor in stabilization. It has been found that actually the presence of martensite is not even necessary for the stabilization to occur. Hence stabilization is possible without prior decomposition of austenite either into bainite or martensite and seems to reflect some internal rearrangement occuring in the parent phase during retarded cooling or isothermal holding.