The methods of spectrophotometry, conductometry and calorimetry have been used to investigate the uranylchloride interaction with tributylphosphate, di-iso-amyl, dioctyl ethers of methylphosphonic acid, trioctylphosphinoxide and hexamethylphosphortriamide in anhydrous acetone medium. The existence of complexes of 1:1 and 1:2 composition is found, constants of formation and dissociation for these substances are calculated and enthalpies of their formation in acetone are determined. The dependence of equivalent electric conductivity of complexes on their concentration in acetone is studied. The analysis of the data obtained proves a regular growth of both complex formation constants and enthalpies of interaction with the growth of the value of donor number of bases. Dissociation constants of complexes do not practically depend on donor properties of phosphorogranic bases studied with the exception of HMFTA. This is most probably connected with the effect of steric factors, rather than the growth of basisity of compound.