The giant resonance region from 10 MeV < E_x < 55 MeV in ¹¹⁰Cd, ¹¹⁶Cd, ¹¹²Sn and ¹²⁴Sn has been studied with inelastic scattering of 240 MeV  α particles at small angles including 0°. Essentially, all of the E0 strength in these nuclei was located. The isotopic dependence of the giant monopole resonance energies was found to be consistent with relativistic and nonrelativistic calculations for interactions with K_nm  ~ 220–240 MeV.