The grain and flour of two Czech and two Polish winter wheats of the same classification were examined. The quality of the grain (evaluated with standard methods), the endosperm microstructure and the size distribution of the starch granules numerically studied with digital image analysis (DIA) methods were determined. The endosperm microstructure was found to be typical for soft (Leguan and Flair), medium (Line 2038), and hard (Begra) wheats. Stronger wheats (Line 2038 and Begra) showed a higher percentage of small B-type starch granules, compared to soft wheats (Leguan and Flair). Direct comparison of the data obtained for Czech and Polish wheats showed only approximate DIA results because of different agricultural and climatic conditions, which strongly influenced the grain properties examined but the same tendency in the variability of endosperm microstructure and starch granule size distribution for hard and soft wheats from both countries was confirmed.