Near-infrared (NIR) spectroscopy and multivariate analysis were applied to estimate the oil content in paraffin streams. On the basis of studies of prepared mixtures, the system NIR/PLS (partial least-squares method) has good predictive capability and could be used to develop an integrated process control for base oils and wax production. The accuracy, difference between predicted and measured oil content, was within 0.5% weight equivalent to that specified in the standard test method ASTM D 721.