The addition of nanoparticles into conventional heat transfer fluids is one of the modern science techniques that offer better heat transfer performance. However, micropolar fluid model is not considered under these nanoparticles effects. Therefore, the main objective of this study is to explore the nanofluids to understand the microstructure and inertial characteristics of nanoparticles. In this paper, heat transfer flow of a micropolar nanofluid mixture containing copper (Cu) and silver (Ag) nanoparticles is investigated over a heated horizontal circular cylinder. The dimensionless governing equations are solved via an implicit finite difference scheme known as Keller-box method. The results of the nanofluid mixture are compared with those with a Newtonian fluid. The effects of different parameters on velocity, angular velocity and temperature are examined graphically for both Cu/Ag-water and Cu/Ag-kerosene oil. Results show that the heat transfer coefficient of the Cu/Ag-kerosene oil nanofluid mixture is larger than that of the Cu/Ag-water nanofluid, when comparison is based on a fixed value of the micro-rotation parameter.