A highly stabilized magnet power supply system is described for magnetic resonance/susceptibility instrumentation, which is capable of providing a current of 0-5 A into a 40 Omega magnet coil together with linear current sweep facilities. This system can easily be adopted for magnets of any resistance. The DC drift is about 1 part in 105 per hour and low-frequency peak-to-peak noise is less than 1 part in 106. Long-term (1 h) nonlinearity in sweep is less than 1%.