The separation of Nd and Dy from nitrate solutions using bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272) was investigated. Selective extraction of Dy(III) over Nd(III) was achieved with Cyanex272 when the HNO3 concentration was 0.001 mol/L. Small amounts of co-loaded Nd(III) were removed by scrubbing with 0.05 mol/L dysprosium nitrate solution. Subsequently, stripping of Dy(III) from loaded Cyanex272 was accomplished using 0.3 mol/L HNO3. The McCabe-Thiele diagrams were constructed for both extraction of Dy(III) with Cyanex272 and stripping with HNO3. Finally, a process to separate Nd and Dy was proposed.