Soricimyxum fegati gen. et sp. n. is a new myxosporean (Myxozoa) species discovered in the liver of shrews, Sorex araneus L., collected in the Bialowieza primeval forest (Poland). Both developmental stages and mature spores were found during a histological study. The infection had about 40% prevalence at the investigated locality. Plasmodia were polysporic. Elongated plasmodia with an average size of 30 by 8 µm occupied bile ducts and larger rounded plasmodia up to 80 µm in diameter were found in liver parenchyma where they most probably entered after the ducts had been destructed. Plasmodia in both locations elicited a vigorous inflammatory reaction. Spores were of an ovoid shape, 7 µm long, 5.4 µm wide and about 3.5 µm thick. They had two shell valves and two equal polar capsules, located in opposite ends of the spore.