New negative temperature coefficient (NTC) ceramics based on CaCu Mn Ti O (0≤x≤1) compositions have been investigated. The grain size of the CaCu Mn Ti O samples decreases at first and then increases with increasing Mn content. The X-ray photoelectron spectroscopy analysis corroborates the presence of Mn and Mn in Mn-doped samples, which results in a decrease in the activation energy. All the NTC thermistors prepared show a linear relationship between the natural logarithm of the resistivity and the reciprocal temperature, indicative of NTC characteristics. The Mn-doped CaCu Mn Ti O NTC thermistors provide various electrical properties, depending on Mn content. The values of ρ , B constant and activation energy of the NTC thermistors are in the range of 2.22×10 -3.22×10 Ω cm, 5488-8031 K, and 0.473-0.692 eV, respectively. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.