In this study, the Manganese zinc ferrite nanoparticles with diameters less than 50 nm were prepared. By XRD (X–ray diffraction), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) the morphology and the structure of this ferrite were studied. The X-ray analysis shows the formation of manganese zinc ferrite in spinel phase. SEM photograph is shown spherical shape of nanoparticles. And the TEM confirmed the nanoscale dimensions of the samples. The manganese zinc ferrite nanoparticles crystallite sizes, calculated by Debye-Scherer formula, were found near 13 nm. Sensitivity properties of this ferrite are investigated in a totally isolated plexi glass box. By injecting 1 mL of liquid and vapor it we will have 200 ppm concentration of each sample in this box. Then the injected vapored sample in this box is exposed to the ferrite. After this step the conductivity of the ferrite in a closed circuit was changed. By changing the sample type amount of this conductivity were varied. Five gases were tested in this project: ethanol, dimethyl formamid, carbon tetrachloride, acetonitrile and acetone. Among these samples the carbon tetrachloride had the best sensitivity performance.