The aim of this study was to check the use of NIR technique for assessment of dry matter (DM) fat (F), crude protein (CP), pH and theological properties of processed cheeses (penetration-P). Samples of processed cheeses were analysed by the reference methods and measured by the FT NIR spectrometer with the fibre optic probe. The calibration models were created using PLS method and verified by cross-validation. The correlation coefficient for DM is 0.998 and those for F, CP, pH and P are 0.995, 0.996, 0.945 and 0.925 respectively. The standard error of the prediction for DM, F, CP, pH and P were found 0.429, 0.997, 0.303, 0.062 and 1.330 respectively. As it follows from obtained results NIR spectroscopy can be used for the determination of the processed cheeses composition. Penetration and pH can be also estimated but with the lower precision. (C) 2003 Elsevier Ltd. All rights reserved.