The isotropic hyperfine shifts induced in the 23Na+ resonance by the shift reagents Dy(DPA)33-, Dy(NTA)23-, Dy(PPP)27-, Tm(PPP)27-, Dy(TTHA)3-, and Tm(TTHA)3- are compared under similar conditions. The last three are introduced as shift reagents in this study. The Dy(PPP)37- and Tm(PPP)27- ions cause the largest shifts. However, these shifts are very pH dependent and are readily decreased by the presence of Ca2+ or Mg2+ ions. The Dy(TTHA)3- and Tm(TTHA)3- ions produce quite large shifts which are independent of pH (between 5.5 and 12) and less sensitive to Ca2+ and Mg2+. For a given chelate ligand, the analogous Dy(III) and Tm(III) complexes cause hyperfine shifts in opposite directions. However, while the Dy(PPP)27- ion induces an upfield shift, the Dy(TTHA)3- ion induces a downfield shift. Some data on shifts of the 25Mg2+, 39K+, and 87Rb+ resonances are also presented. In addition the 14N peak of NH4+ can be quite effectively shifted.