Spinel-perovskite magnetoelectric (ME) nanocomposites xMgFe(2)O(4)-(1-x)BiFeO3, x=0.1, 0.2, 0.3, and 0.4 were synthesized by sol-gel method and characterized by differential thermal analysis, X-ray diffraction analysis, dielectric and magnetic measurements. The samples were calcined at various temperatures and then the effect of annealing temperature on structural and magnetic properties was studied. From transmission electron microscopy, the average crystal size was found to be 30-50nm. The magnetic behavior is found to be dependent on annealing temperature and magnesium ferrite content. The dielectric behavior with frequency and temperature has been modified with the induction of magnesium ferrite. The relative change of dielectric constant with magnetic field was observed in the nanocomposites. This relative change of magnetic field-induced dielectric constant can also be expressed by epsilon similar to M-2 (where is magnetoelectric coupling coefficient).