The possibility of using near-infrared (NIR) spectroscopy for monitoring of liquid whey quality parameters during protein production process has been tested. The parameters included total solids, lactose, protein and fat content. The samples for the experiment were taken from real industrial processes and had a large variability for most of the parameters. Partial Least Squares (PLS) regression was used to make the prediction models based on NIR spectra taken at 30 and 40 °C. Using proper wavelength range allowed to get models for prediction of fat, protein and amount of total solids with very high precision and accuracy. The lactose was found to be the most challenging parameter.