Abstract <p>Complex morphological and dimensional profiling of extracellular vesicles of human gastric juice by cryo-electron microscopy has been performed. It has been shown that in gastric cancer, the proportion of classical individual vesicles surrounded by a single layer of the plasma membrane increases statistically significantly (up to 74% versus 40% in healthy controls), while the representation of multilayer forms decreases. A comparative analysis of data from cryo-electron microscopy and analysis of nanoparticle trajectories has been carried out, demonstrating that cryo-electron microscopy reveals a significantly higher proportion of particles in the range of 40–70 nm. Thus, the paper describes for the first time the composition of extracellular vesicles of gastric juice and reveals significant differences in the morphological distribution between the norm and pathology, as well as systematic discrepancies between the methods of cryo-electron microscopy and analysis of nanoparticle trajectories in the direction of greater sensitivity of cryo-electron microscopy to small vesicles.</p>