<p>We describe a new method for the measurement of U/Pb ratios by isotope dilution multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) for the dating of geologically young clean carbonates, particularly speleothems. The method is intended for materials containing little or no initial <sup>232</sup>Th. We illustrate and validate the method with four examples ranging from 0.57 Ma to 20 Ma old. The new method is capable of applying the <sup>235</sup>U-<sup>207</sup> and <sup>238</sup>U-<sup>234</sup>U-<sup>206</sup>Pb chronometers, common Pb and quantifiable residual <sup>234</sup>U/<sup>238</sup>U disequilibrium permitting. These provide an alternative to the more widely used <sup>238</sup>U-<sup>206</sup>Pb chronometer, which can be highly inaccurate for samples a few million years old, owing to uncertainties in the excess initial <sup>234</sup>U (hence, excess radiogenic <sup>206</sup>Pb) commonly observed in speleothems.</p>