Nanosized magnesium ferrite MgFe2O4 was synthesized using sol-gel auto combustion method as a burnt powder calcined at different temperatures (350, 500, 650, 800 and 950 C˚). These powders were pressed into a disk shape compact, and sintered at 1100 C˚ for 3 hours. The X-ray diffraction patterns of the ferrite powders showed the formation of spinal cubic structure, whereas the crystallite size increased with increasing calcined temperatures from 29 to 42 nm. The absorption bands of the FTIR spectra of all the ferrite powders showed that the magnesium ferrite had two absorption bands within the range of (408.9 – 563.2 cm-1) for high and low frequencies. The dielectric constant, dielectric loss and ac conductivity for the sample sintered at (1100 C˚) were studied as a function of frequency at room temperature by using LCR meter. The variation of dielectric properties at frequencies from 50Hz to 1MHz has been explained on the basis of Koop’s theory. Maxwell-Wagner polarization process at hopping of electrons for all the dielectric properties indicated normal behavior with increasing the frequency. The particle size represented by AFM was found to be within the range of (67.49 nm), and the square root of the average roughness was directly of proportional particle size and granular boundary limitations.