Solvent extraction behaviors of Se (VI) from nitric acid solutions were investigated with multiple extractants used for uranium, plutonium, minor actinides, and rare earth elements separation processes from high-level liquid waste. During the processes, Se remained in the residual aqueous solutions, as all extractants showed distribution ratios < 1. In contrast, Se showed distribution ratios > 1 with o-phenylenediamine in dilute nitric acid (< 2 M HNO3), octanol as the organic phase, and concentrated nitric acid (8 M HNO3) for back extraction, suggesting a potential new single separation process and recovery of Se.