The solvent extraction of Pr, Gd, and Yb with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and an amine salt (AmHA) has been studied. The composition of the extracted species has been determined as (AmH)[LnP(4)]. The values of the synergistic coefficients and separation factors have been calculated. The effect of the amine salt on the extraction and separation of lanthanides has been discussed.