This paper reports the results of a numerical and experimental investigation of mixed convection from a heat-generating element in a vented cavity with/without a baffle arrangement. Numerical investigations are carried out to determine the best position of the baffle on the walls of a rectangular chamber. The effect of varying the baffle heights and the position on the enhancement of heat transfer from the heater is investigated. Experiments were carried out for a heater located centrally in a parallelepiped that has an air inlet and an outlet port. The vertical baffle is fixed on the bottom wall of the chamber. After a detailed parametric study, correlations have been developed for the average Nusselt number and the maximum dimensionless temperature occurring in the heat generating element. Comparison of the numerical and experimental results for the geometry considered showed good agreement. © 2009 Springer-Verlag.