With the increase in diameter of the wafers and the tendency to increase operating pressure of chemical vapor deposition reactors, the flow in these reactors may turn turbulent as a result of buoyancy. The effect of turbulence on the CVD process in a single wafer reactor has been studied numerically with large eddy simulations. It is found that the free-convection induced turbulence increases the heat flux, whereas the conditions are uniform in a large part of the reactor as a result of turbulent mixing, in principle offering the possibilities for a high, uniform deposition rate.