[en] Uranyl extraction with ethers, esters, ketones and alcohols has been considered. The equation has been proposed for calculating thermodynamic distribution constants which takes into account the effect of co-extracted water on the activity of uranyl nitrate in the organic phase. It has been established that the equation describes satisfactorily the extraction isotherms when salt concentration changes from diluted water solutions up to saturated ones. Irrespective of the extragent nature, the linear relationship is observed between the parameters of the equation: the greater the deviation of the organic phase from ideal, the higher the distribution constant determined respecting the water-saturated solutions in the extragent