The effect of various compositions of solvents was investigated on the electron beam induced synthesis of uranium dioxide, UO₂ nanoparticles. The synthesis was carried out at different pHs from 2 to 7 in the aqueous solutions containing 10m Muranylnitrate and 10% 2-propanol. The formation of UO₂ nano-particles was found to occur only in the pH range from 2.5 to 3.7. Experiments were also carried out in the aqueous solutions containing various other alcohols (10%v/v) such as methanol, ethanol, 1-propanol, 1-butanol or tert-butanol as well as in solutions containing 10mM sodium formate at pH3.4. The formation of UO₂ nano particles in the aqueous solutions was found to occur only in the presence of ethanol, 1-propanol, 2-propanol or 1-butanol. It is therefore confirmed that the electron beam induced synthesis of UO₂ nano particles strongly depends on the solvent compositions as well as the pH of the medium.