Isotopic data in this database includes 863 samples from 34 papers and three previously published compilations. For each sample, this database provides location, age, and reference information presented in the first columns. Locations are recorded in latitude and longitude (WGS84). The information about the location source uses the same criteria used for the elemental geochemical database (“GPS”, “Figure-Polygon” and “Figure-Point”). Age is provided according to the original source and includes two general scenarios: an age with uncertainty at 2σ level and a general estimation for the age with no associated error. Sm-Nd and Rb-Sr data are based on whole rock analysis. Lu-Hf data are based on zircon analysis. Sm-Nd data includes Sm and Nd in ppm, 147Nd/144Nd and 143Nd/144Nd in ratios, Nd uncertainties at 2σ level, and Nd values in the epsilon notation as presented in the data source. Rb-Sr data include Rb and Sr in ppm; 87Rb/86Sr, 87Sr/86Sr, and initial 87Sr/86Sr in ratios, and Sr uncertainties at 2σ level. Lu-Hf data includes 176Yb/177Hf, 176Lu/177Hf, and 176Hf/177Hf rations and their uncertainties at 2σ level, the initial 176/177Hf ratio, Hf values in the epsilon notation and Hf uncertainties at 1σ and 2σ level, all as presented in the data source. Uncertainties related to the data location and heterogenous data distribution should be considered. Samples for the two batholiths in Mongolia are concentrated in central Mongolia and include Sm-Nd and Lu-Hf data. In the Erguna and Xing’an magmatic provinces, available samples provide mainly Lu-Hf data which are relatively better distributed than in the other regions.