The sensitivity of Near Infrared Spectroscopy (NIRS) signals to motion artifact can limit practical applications of NIRS monitoring. We describe a wavelet based method for removing motion artifact from NIRS signals. This method was tested on monitoring data collected from leg muscle in 3 patients undergoing surgery to stabilize leg fractures. The results show an average of 18.36 dB attenuation in motion artifact energy in the NIRS signal for our test subjects when using the proposed method, without the introduction of significant distortion in the artifact-free regions of the signal.