Prions form an infectious version of amyloid; they are involved in the pathogenesis of some human neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. Yeast prions, in particular, the Sup35 protein, serve an effective model for studying the basic properties of amyloids. Strain versions of the prion form of Sup35 lie in the basis of the conformational diversity of the amyloid structures formed by it, which exhibit different biological properties. The spatial organization of the Sup35 prion has not yet been established. The structure of the strain version W of Sup35 prion protein, isolated ex vivo from yeast Saccharomyces cerevisiae , was studied by transmission electron microscopy (TEM). The parameters of the fibril were estimated, and its structure was reconstructed with a low resolution.