The shell pores of Baikalian euglesid bivalves from the littoral of South Baikal Lake were for the first time studied with the SEM. It was shown that the pores are unevenly distributed in the 8 species studied [Henslowiana semenkevitschi (Lindholm, 1909), H. trigonoides (W. Dybowski, 1902), Euglesa granum (Lindholm, 1909), E. minuta (Kozhov, 1936), E. korotnevi (Lindholm, 1909), E. platyvalva (Slugina et Starobogatov, 1994), Cingulipisidium koshovi (Starobogatov et Streletzkaja, 1967), Conventus raddei (W. Dybowski, 1902)]. In subumbonal part of E. granum and E. minuta shells, the pore density is 1.5 times higher; the pore width and height in E. minuta are about 2 times more above the mantle line than in marginal part of the shell. The pores in subumbonal part of E. platyvalva shell are, on the contrary, 1.5 rarer than above the mantle line and 2.6 times rarer than at the shell margin. Among the species studied, only E. platyvalva has pores between the mantle line and the lower valve margin, which has not been previously found in the family Euglesidae. In the subumbonal part of this species shell the largest pores were observed: 6.34 μm, whereas the smallest pores in this part of the shell were found in С. kozhovi (2.22 μm). The pores of three species, H. semenkevitschi, E. granum, C. koshovi, are surrounded by additional thickening on inner side of valves.