Residual grease levels and moisture content of commercially scoured wools have been estimated using spectroscopic methods over the wavelength range 400 to 2500 nm using both transmission and reflectance techniques. The most reliable predictive equations come from the longer wavelength region ( 1100-2500 nm), and reflectance measurements are more satisfactory than transmission measurements. Also, the com monly used algorithms for calculating prediction equations tend to give similar values of SEP (standard error of performance), suggesting that the calibration population coverage and the quality of the data from the reference method are the main deter minants of the quality of NIR-based predictions.