The solubility of nickel ferrite and zinc ferrite in an aqueous solution of acetic acid was studied gravimmetrically by varying the concentration of acetic acid at diferent temperatures ranging from 25 to 45 °C. The molar solubility and thermodynamic parameters of nano nickel and nano zinc ferrites have been evaluated. In this work, we observed how the concentration of CH3COOH and temperature afected the solubility of nano nickel and nano zinc ferrites at temperatures of 298, 303, 308, 313, 318 K. The two ferrites were prepared by sol–gel method. Structure and particle size of the reaction products were determined by X-ray difraction and TEM analysis. It was found that the two ferrites were pure powder of NiFe2O4 and ZnFe2O4 with a cubic structure with mean particle size 21 and 30 nm respectively. The solubility of the two ferrites in diferent solutions of CH3COOH was measured gravimmetrically by the evaporation process using I.R. Lamp. It was found that the solubility increased with an increasing mole fraction of diferent CH3COOH solutions and increased also with increasing of temperature due to more solvation process. All solvation parameters were discussed. We need to mix the two nano ferrites in a safe solvent for diferent cancer chemotherapy treatment. The aim of the work is to dissolve the very insoluble nano nickel and nano zinc ferrites in weak acid like acetic acid,which is used in hyperthermia and also kill cancer tumors. Also the uses of nano ferrites as magnetic fuid hyperthermia agents and good carriers for chemotherapeutic agent. The aim of this work is to dissolve the very insoluble nano nickel and nano zinc ferrites prepared by sol–gel in CH3COOH at diferent concentrations, then we can neutralize the excess acid. The target of this work is to increase the solubility of both nano nickel and nano zinc ferrites with increasing temperature. The aim also in this work is to give the helpful nickel nano ferrite data necessary for hyperthermia and killing cancer tumors, especially in the skin.