The extraction of europium(III), dysprosium(III), and gadolinium(III) nitrates with di-(2-ethylhexyl) phosphoric acid (D2EHPA) in o-xylene was investigated at 298.15 K. Spectrophotometry and ICP-AES techniques were used for rare earth elements (REE) content determination. The content of nitric acid was measured by acid-base titration. The density of the equilibrium phases was determined. In the case of high content of rare earth element nitrates in the initial aqueous solutions, the third solid phase formation was observed during extraction experiments.