The numerical optimization-scheme developed previously is successfully applied to optimize the geometric shape of a horizontal metal-organic chemical vapor deposition reactor for a uniform epitaxial layer of compound material. The procedure is based on sequential linear programming in which the reactor shape is approximated by the Chebyshev polynomials. A SIMPLE-type finite volume method is used on a general nonorthogonal grid to obtain the flow characteristics by solving the fully elliptic momentum, energy, and concentration equations. It has been demonstrated that more than a 30-fold improvement in uniformity can be achieved by this optimization for various flow and geometric conditions considered in this study. The optimization is also found effective for mixed convection flows as the buoyancy driven recirculation may be suppressed completely. (C) 2000 Elsevier Science Ltd. All rights reserved.