This dataset lists the oxygen isotope ratios used to update the age model of Integrated Ocean Drilling Program Site U1313 (41°N, 33°W, 3426 m water depth, Expedition 306) for the Mid-Pleistocene Transition interval (0.55 Ma - 1.2 Ma). Tests of C. wuellerstorfi and U. peregrina were picked, crushed, and analyzed at the Institut für Geowissenschaften, Universität Heidelberg, Germany. The standard deviations (reproducibility) for repeated measurements of the in-house standard were 0.08‰ for δ18O. The standard deviations (reproducibility; n=10) for repeated sample measurements were also 0.08‰ for δ18O. To allow for a continuous record comprising data of both species, δ18O values of Cibicidoides wuellerstorfi were corrected to bottom-water δ18O values by adding 0.64‰. To this dataset were added data points produced by Naafs et al. (2011) and Ferretti et al. (2015, from the secondary splice) for depth-age conversion. The combined and species-adjusted benthic δ18O record of Site U1313 to the LR04 benthic stack (Lisiecki and Raymo, 2005) using the software AnalySeries 2.0.8 (Paillard et al., 2011).