Nanocrystalline Mn 0 . 5 Zn 0 . 5 Fe 2 O 4 ferrite in SiO 2 matrix has been prepared by sol-gel method. X-ray diffraction (XRD) study indicates the presence of single-phase spinel ferrite in the sample. The size of the particles, estimated by a transmission electron microscope (TEM), was found to be less that 20nm. The magnetization measurement of the sample shows no hysteresis loss. The Mossbauer spectra consist of a sextet due to ferromagnetic particles and a doublet due to superparamagnetic nano-sized ferrite.