Whole-rock sulfur isotopic ratios were determined for four magnetite-series and two ilmenite-series granitoids from the central Sierra Nevada batholith. The magnetite-series rocks yielded δ34S(CDT) of 1.6‰ to 4.0‰, and the ilmenite-series rocks revealed lower values of -3.7‰ and -5.3‰. These correlations are the same as those observed in the Japanese Islands arc. A majority of the Sierra Nevada granitoids are considered to have positive 34S values as a result of island-arc magmatism. The same magma was reduced by the introduction of organic carbon from the sedimentary wall rocks along the western zone where the depth of granitoid emplacement was as deep as 4-5 kbar, thus forming the ilmenite-series granitoids.