Three-dimensional conjugate heat transfer in a rectangular duct with two discrete flush-mounted heat sources has been studied numerically in the context of cooling of electronic equipments. The Grashof number is fixed as and the working fluid is taken as air. The effects of the spatial arrangement of heat sources, the thermal conductivity ratio of the bottom plate material to air, and the Reynolds numbers on the overall and local heat transfer in the duct are evaluated. The magnitudes of the conduction and the convection transport are compared for different parametric combinations. Of particular interest are the transverse variation in the flow, temperature and heat transfer, the interaction between the heat sources, and the effects of conjugate transport.