In this study, flow characteristics and natural convection in a cavity with two wavy walls is studied numerically. The wavy walls of the cavity are isothermal and at different temperatures while other straight walls are adiabatic. The fluid considered inside the cavity is air having Prandtl number of 0.71. A parametric study is conducted for various aspect ratios (1 <= AR <= 5), Rayleigh numbers (10(3) <= Ra-H <= 10(6)) and inclination angles (0 degrees <= theta <= 180 degrees). Streamlines, isotherms and local and mean Nusselt numbers are presented to show the effect of the investigated parameters on the flow field and heat transfer.