We describe a methodology to correct the apparent shift in temperature below 4K of Cernox 1030 resistance thermometers in magnetic fields up to 9T. A Lakeshore 340 temperature controller is used to measure the electrical resistance of the thermometer by passing an electric current through it. In zero magnetic field, this resistance is converted into temperature using the manufacturer?s calibration. In high magnetic fields the magnetoresistance of the thermometer invalidates the calibration. We measured the apparent temperature vs. magnetic field of two Cernox 1030 thermometers at several (nearly) constant temperatures. We describe how we convert these apparent temperatures in field to thermodynamic temperatures.