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A new quantitative approach is proposed for estimating palaeoprecipitation across the Chinese Loess Plateau. At present, there is a strong rainfall gradient across the plateau from ∼ 300 mm/yr in the near-desert conditions in the northwest to over ∼ 750 mm/yr in the southeast, just 700 km distant. We find that the concentration of ferrimagnetic iron oxide minerals in nine modern soil types (represented by 37 individual soil profiles) is strongly correlated with this contemporary rainfall gradient. The ferrimagnetic concentration rises along this gradient, from 0.01% in the northwest to over 0.2% in the southeast. The nine modern soil types have been used in the construction of a rainfall vs. magnetic susceptibility (least squares regression) climofunction. Past variations of loess-soil iron oxide content are easily established through magnetic susceptibility measurements and so can be used to reconstruct the rainfall of …