The paper presents new data on the upper Silurian litho- and biostratigraphy of the Gorny Altai area. Sediments within this interval store a succession of taxonomically representative middle-upper Ludfordian, lower Pridoli, and Lower Devonian (Lochkovian-Pragian) conodont assemblages. The new fauna constraints made a basis for updated correlations of the local and regional stratigraphic units at the Silurian/Devonian boundary of Gorny Altai with the stages of the International Stratigraphic Chart. The correlation results reveal a mismatch between the boundaries of the local and regional Silurian units and the respective boundaries of stages in the International Stratigraphic Chart.