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Conventional multigrain and single-grain zircon U-Pb ages were obtained for syn- and post-metamorphic granitoids from the Sludyanskiy Complex in the South-Western Baikal region regarded as a classical Precambrian terrain in the Eastern Siberia. Single grains of magmatic zircon from the syn-metamorphic hypersthene-bearing biotite trondhjemite and two-pyroxene trondhjemite have yielded concordant U-Pb ages of 488.5±0.6 Ma and 488±0.5 Ma. Concordant U-Pb data for zircons of metamorphic origin in the syn-metamorphic two-pyroxene trondhjemite yield an age for the peak of the granulite-facies metamorphism in the Sludyanskiy Complex as 477.6±2 Ma. The pattern of multigrain magmatic zircon samples from syn-metamorphic granitoids reflects significant Pb loss during the metamorphic episode. This came to an end before 471.1±2 Ma as demonstrated by concordant zircon data for the intrusion of post-metamorphic amphibole-two-pyroxene quartz syenite.