In this study, copper manganese oxide films with various compositions were synthesized using electrochemical deposition technique. In order to achieve different chemical compositions, the influence of sodium citrate as a complex agent was investigated. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Brunauer-Emmet-Teller adsorption (BET) were used to study the morphology, chemical composition, crystal structure and surface area of deposited layers, respectively. We observed that by optimizing the citrate concentration in the electrodeposition electrolyte, improved capacitance of 744 F/g at 10 mV/s with retention capacitance of 91% over 10,000 cycles can be achieved. The obtained stability of copper-manganese oxide is 3 times and about 2 times higher than pristine copper oxide and manganese oxide, respectively. The enhanced stability of the achieved crystalline copper-manganese oxide ascribe to formation of CuMn2O4 spinel, improved ultrafine structure and a better chemical stability. Display omitted •Synthesis of spinel structure beside of other metal oxides, by one step, without using the heat treatment process.•Investigation of the effect of complex agent concentration on the structure and compounds containing copper-manganese oxide.•CuMn2O4 exhibited better cyclic stability than composite of copper oxide and manganese oxide.•Investigation of capacitive properties of synthesized composites.