The work presents an analysis of potato tuber density change taking into account the impact of many factors. The tests were performed using a method involving density assessment with reference to single tubers. The examination covered two tuber fractions, three potato varieties, fertilised with mineral and pro-ecological fertilizers. The measurements were taken for eight months, in one-month intervals. The tests were carried out between 2001 and 2004. The results prove that all the factors assumed in the experiment had statistically significant effect on the density value. Higher density was discovered in smaller tubers, after vegetation in insufficient rainwater amount conditions, fertilised with mineral fertilizers. Tuber density was increasing during extended storage periods, and the course of these changes was expressed with second degree polynomial equations.