The objective of the presented research was to explain the impact of temperature of water sorbed by ready-to-cook potato chips semi-products on change in their density. The research was carried out for samples in the form of matchsticks cut along the direction between the top part of a tuber and its navel. Matchsticks with cross-section of 10x10mm were subjected to sorption process (by dipping them) in water with temperature of 20, 30, 40, 50oC. The research involved determination of density before the process and during it; the measurements were carried out every 2 min. Sorption duration was 12 min. The tests were conducted during storage period of 2008/09, between October and April. Ready-to-cook products used to make chips were formed of the Kuklik variety tubers. Analysis of test results indicates statistically significant impact of chosen experiment factors on change in the density of ready-to-cook products for chips. Their density was dropping as a result of water sorption. Density was decreasing with increasing temperature and water sorption in the examined value ranges. Density loss values were different, depending on storage period: they were decreasing between November and January, and increasing between January and April. Obtained trajectories of functions estimated with reference to real values of the experiment are well adjusted. The share of variance explained for individual function trajectories, resulting from experiment combination, ranged from 0.648 to 0.966.