This present work concerns the study of laminar mixed convection in lid-driven cavities filled with Cu-water nanofluid. Each cavity is heated by two heat sources placed on vertical walls at a constant heat flux q. The top wall moved with uniform velocity of U0. The top and bottom walls of the cavity are maintained at a local cold temperature TC, respectively. The continuity, Navier-Stokes, and energy equations are all solved by using the finite volume method. A computer program is developed and compared with the numerical results found in the literature. Results are presented in terms of streamlines, isotherms, vertical velocity profile, and average Nusselt numbers at a fixed Reynolds number (Re=10) and for Rayleigh numbers in the range (Ra=10 3 -10 6 ), solid volume fractions of nanoparticles (=0-0.20) and different aspect ratios (AR=0.5-4). It is found that the average Nusselt number increases with the increase of the Rayleigh number, solid volume fraction and aspect ratio of the cavity.