Relevance. Potato are one of the main sources of starch. Potato starch is widely used in human economic activities. The starch content in tubers, including the number of starch granules and their size and shape, are varietal characteristics. For this reason, it is important to identify potato varieties with starch grains suitable for starch production already at the early stages of breeding process.Materials and Methods. The Aim was to study the morphological structure of starch granules in cells of potato tubers belonging to varieties from different maturity groups. Eighteen potato varieties (Solanum tuberosum L.) of various breeding origin and from different maturity groups were used as the research object. The granulometric composition was determined by the method of fluorescent microscopy. The research was conducted using a CLSM 800 confocal laser scanning microscope (Zeiss, Germany) with a laser wavelength of 488 nm.Results. The research allowed us to obtain data on the morphology of variously-shaped starch granules in cells: round, oval, elongated, and irregular. The research established a direct correlation between the number of large starch grains in a cell and the time required for a given potato genotype to mature. Mid-season and medium late potato varieties were observed to have a higher starch content than varieties from the groups with earlier maturity. On average, the difference in the starch content between these groups was 1.97%. The highest number of starch grains was found in 40-70 μm cells and larger. The research identified Solanum tuberosum L. genotypes with large and small starch granules. These genotypes might be recommended for further use in the practical breeding to create high-quality varieties.