The results of Sm–Nd studies of metasedimentary rocks from the Tukuringra terrane, one of the largest units in the structure of the eastern part of the Mongolian–Okhotsk mobile belt, are reported. Metasedimentary rocks of the Algainskaya, Garmakanskaya, and Teploklyuchevskaya formations are characterized by similar model ages t Nd( DM ) = 1.5–1.1 Ga. This shows that the major protoliths of metasedimentary rocks of the terrane are characterized by Mesoproterozoic estimates of the Nd model ages. The results obtained allow us to assume that introduction of terrigenous material into the sedimentary basin mostly occurred from the continental massifs united into the Amur superterrane, since their magmatic and sedimentary complexes are characterized by identical values of the Nd model ages.