The elemental partitioning characteristics of advanced single-crystal Ni-base superalloys containing additions of both Pt and Ru have been investigated using atom probe tomography. Detailed microanalysis revealed Ru additions partitioned preferentially to the disordered γ matrix, whereas Pt additions tended to partition to the ordered intermetallic γ′ precipitates. The stability of the γ′ precipitates at elevated temperatures coupled with the subtle changes in elemental partitioning associated with the additions of Cr and Ru were found to significantly influence the bare metal cyclic oxidation behavior of the experimental single-crystal alloys. Although the presence of Pt was observed to greatly enhance oxidation characteristics, these beneficial gains were impacted by Cr and Ru additions as they both increased the tendency for oxide spallation during cyclic thermal exposures.