By using the theoretical relationship between attenuation and depolarisation, a cumulative distribution of depolarisation can be predicted from a distribution of attenuation at the same frequency. In the case of earth-space paths, however, it was found that there is poor correlation between measured attenuation and XPD because of so called ice depolarisation. This implies that the predicted XPD value for an earthspace path includes an error if the theoretical relationship between rain attenuation and XPD is used.In this paper, a new method of predicting cumulative distributions of XPD is proposed in which the effects of the ice depolarisation are taken into consideration by using the factor of ‘ice depolarisation ratio’. The applicability of this depolarisation prediction method is verified by using attenuation and depolarisation statistics which have been measured in some wave propagation experiments along earth-space paths.