The application of shape optimization techniques to reduce the weight of a power-take-off (PTO) casting housing has been presented. Shape vectors required for optimization were generated by numerical interpolation method using Autodv software. Shape optimization is performed in MSC/NASTRAN using ‘Direct Linearization’ method. The weight of the casting housing has been reduced by 40%. In conclusion, shape optimization techniques can be used to reduce the weight of any casting, which is non-uniform in shape and size.