Nanomaterials have attracted wide attention due to their promising characteristics in contrast to their bulk counterparts. However, techniques for their synthesis need to be explored further for their application in promising nanomaterial-based devices. Herein, a simple hydrothermal technique was developed for the synthesis of FeO nanoparticles utilizing nanoscale MnO as a template. It was found that the redox chemical conditions employed for the synthesis of nanostructured MnO are also applicable for the fabrication of FeO nanostructures. Subsequently, HRTEM, XRD and XPS analyses were conducted, which confirmed the presence of morphologically reduced FeO. Furthermore, the electrochemical analysis revealed the promising supercapacitive behaviour of 590 F g at a current density of 2.9 A g for the as-synthesised MnO/FeO nanocomposite. This high performance can be attributed to the favourable characteristics of the developed nanomaterial such as high specific surface area, abundant active sites and short diffusion paths for charges.