Magnetic properties of a nickel‐zinc ferrite (15% NiO, 35% ZnO, 50% Fe2O3) were measured over a temperature range of 23°C to 110°C at hydrostatic pressures up to 40 000 psi.The relation between the shift in Curie temperature, &Dgr;Tc, and the change in pressure, &Dgr;p, was empirically found to be&Dgr;Tc=0.078(&Dgr;p)0.316.It is shown that if magnetic anisotropy and internal strains limit the magnetizing processes, the relation between coercive force,Hc, maximum flux density,Bm, and initial permeability, &mgr;0, is given byHc=&dgr;Bm/&mgr;0,where &dgr; is a proportionality constant. The experimental results obtained over the entire range of temperature and pressure verify the above relation. The value of &dgr; is 2.56 for the ferrite investigated.