Results of determination of the minimum number of cells necessary for the quantitative determination of geometrical parameters of the potato tuber parenchyma structure have been presente. The study material consisted of 4 potato varieties over a three-year crop cycle. Microscopic images of tissue in its natural state were obtained by means of an optical confocal microscope. Several thousand cells were used for the analysis of the structure parameters. The surface distribution of flat cell cross-sections was obtained by means of specialist 'APHELION' software. A minimum number of cells determined by comparison carried out between empirical surface areas of flat cell cross-sections for a big database ensuring the randomness of the samples provided according to the following scheme: 200 (2´100), 400 (2´200), 600 (2´300), 800 (2´400) of cells by means of the 'Kolmogorov-Smirnov l Compatibility Test'.